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LIBRARY OF THE
NEW YORK STATE COLLEGE
OF HOME ECONOMICS

CORNELL UNIVERSITY
ITHACA, NEW YORK

Cornell University Library
TP 146.A6

Elementary applied chemistry,

3 1924 003 619 032

RETURN TO
ALBERT R. MANN LIBRARY

ITHACA, N. Y.

Cornell University
Jbrary

The original of tliis book is in
tine Cornell University Library.

There are no known copyright restrictions in
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http://www.archive.org/details/cu31924003619032

ELEMENTARY
APPLIED CHEMISTRY

LEWIS B. ALLYN

DEPAKTMENT OF CHEMISTRY, STATE NORMAL SCHOOL
WESTPIELD, MASSACHUSETTS

' For the world was built in order
And the atoms march in tune."
— Emerson

GINN AND COMPANY

BOSTON • NEW YORK ■ CHICAGO • LONDON

LEWIS B. ALLYN

gbe attenaum grea*

CINN AND COMPANY • PRO-
PRIETORS • BOSTOIf ■ U.S.A.

PREFATORY NOTE

The object of the exercises in this book is to create and
to foster a real love for and interest in the great science of
chemistry, to give the pupil a broader outlook on life,
and to cause him to feel that he is a factor in the busy,
living world.

These experiments and tests have been of personal value
to hundreds of earnest students ; possibly they may be of
value to you. If you know of some one who would profit
by the information you may receive, pass it on.

CONTENTS

SECTION PAGE

I. Filtration . . . . . •. . 1

II. Acids and Alkalis 5

III. Alkalis in Textile Analysis ... 7

IV. Acids and Alkalis in the Qualitative Analysis or

Soils . . . . . ... . 9

V. Detection or some of the Compounds present in

Plants . . . . 13

VI. Exercises with Standard Solutions . . . 16

VII. Sanitary' Analysis or Water . 28

VIII. Examination of Baking Powder . 3-5

IX. Analysis of Milk . . .41

X. Examination of Ice Cream, Cheese, and Condensed

Milk ... 52

XI. Distillation Experiments 54

XII. Detection of Coal-Tar Dye . . 76

XIII. Identification of Vegetable Colors 79

XIV. Raffia Dyeing . ... 81
XV. Chemistry of Stains . . . 88

XVI. Food Preservatives ... 90

XVII. Examination of Tooth Powders ... . 95

XVIII. Experiments with Glucose .... . . 97

XIX. Examination of Headache Powders . . . 102

XX. Tests for Arsenic ... 105

XXI. Method for testing Paint and Oils . ... 109

XXII. Determination of Food Values 113

XXIII. Testing Urine . 118

XXIV. Selected Exercises . ... 120

INDEX 125

SUGGESTIONS TO TEACHER AND PUPIL

Be sure that the work done is correct, and then certify it.

The use of blanks similar to the one on page x gives a
suggestion of importance to the task performed and is con-
ducive to honest, accurate work, and, best of all, to a regard
for the truth.

Much time will be saved by making counterpoises with
stoppered vials and fine shot for beakers, crucibles, evap-
orating dishes and specific-gravity flasks. Test the accuracy
of these tares occasionally.

If you are not sure of a reaction, -work with a sample
which is known to contain the substance in question. For
example, if the odor of phenylcarbamine is unkrtown, heat
a few drops of commercial anilin with 5 cc. of stock solution
of KOH. Add a cubic centimeter of chloroform, agitate
gently, cool, and note the odor.

Form the habit of using a pipette instead of a graduate
whenever special accuracy is desired.

Distilled water should be used for dilutions and solu-
tions, especially for solutions of precision.

Many semifluid substances may be ashed by allowing
the flame to strike the surface of the material, meanwhile
applying a gentle heat to the bottom of the crucible.

Save products and samples. Bottle and label them. A
collection is an inspiration and an incentive.

Notebooks should be illustrated by mounted samples,
cuts, and clippings from newspapers and magazines.

ELEMENTARY APPLIED CHEMISTRY
REPORT OF CHEMICAL ANALYSIS

Sample.

Obtained froni_

Manufactured by_

Reaction . . .

Test

Coal-tar dye

Vegetable colors . . . .

f ethyl
AlcohoH

L methyl . . .

Jlineral matter or metals .

Organic compounds (iniscellaneou.s) .

Bases . ... . . .

Radicals .... . .

Essential oils

Preservatives

Glucose .

Acetanilid or phenacetin

Equation . . . .

C fraudulent . . .
Adulteration-;

l^ injurious

Quality

KEMARKS

I hereby certify that the above is coi-rect to the best of my knowledge.

Name

Date 19

SUGGESTIONS TO TEACHER AND PUPIL xi

Much collateral reading should be encouraged. The
following books and pamphlets are valuable :

Leach, A. E. Food Inspection and Analysis. John Wiley & Sons.

Wiley, H. W. Foods and their Adulteration. Blakiston.

Blyth, a. W. Foods, their Composition and Analysis. D. Van
Nostrand Company.

Pearson. Jensen's Milk Hygiene. J. B. Lippincott.

Olsen, J. C. Pure Foods. Ginn and Company.

Olsen, J. C. Quantitative Chemical Analysis. D. Van Nostrand
Company.

Snyder. Human Foods. The Macmillan Company.

Allen, A. H. Commercial Organic Analysis. D. Van Nostrand
Company.

CoHN. Tests and Reagents. John Wiley & Sons.

Bulletin No. 107, Bureau of Chemistry, United States Department
of Agriculture.

ELEMEI^TARY APPLIED
CHEMISTRY

SECTION I
FILTRATION

Application to Qualitative and Quantitative Analysis (2-Part
CQmpound). A very satisfactory remedy for tonsillitis is a
mixture consisting of equal parts of sulfur and powdered
sugar. This is a recognized specific, and at one time was
sold as a patent medicine at fifty cents per ounce. The
instructor should prepare a quantity of the specific, varying
the proportions slightly. Pass the mixture several times
|ihrough a fine sieve.

(a) Qualitative Work. Place a spoonful of the powder in
a beaker. Add 50 cc. of water, boil, and filter. Test both
filtrate and residue in any way you choose. Of what is the
powder composed ? How do you know ?

Copy and sign the following statement:

I hereby certify that a mixture called Tonsillitis Specific and
examined by me contains

Name

Date

(V) Quantitative Work. Weigh as exactly as possible
3 to 5 g. of the specific upon a carefully balanced filter
paper. Adjust to a funnel and wash with repeated portions
of hot water until the filtrate ceases to darken when a few

2 ELEMENTARY APPLIED CHEMISTRY

drops are heated with strong H^SO^ ; or until a drop leaves
no dark-colored residue when evaporated upon a piece of
platinum foil.

Dry the residue over a water bath ; remove and cool.

Place the duplicate filter paper in the opposite scale pan
and weigh the sulfur directly. Determine the weight of
the sugar by difference.

Copy and sign the following, or use a printed blank :

The sample of Tonsillitis Specific as analyzed by me contains

per cent sulfur, per cent sugar.

I hereby certify that the above is correct to the best of my

knowledge.

Name .

Application to the Analysis of a 3-Part Compound, (a) In-
troduce a definite amount of gunpowder (2 to 3 g.) into a
balanced filter paper. Wash with repeated portions of hot
water. Test the filtrate for residue with the platinum foil as
before, using only a drop or so for the test. Collect the filtrate
and evaporate it to dryness in a tared evaporating dish.

(by Dry the residue remaining in the filter paper. Ex-
tinguish *aH flame in the vicinity, and wash the residue with
tlu-ee or four 10-cc. portions of CS^. Collect filtrate No. 2
in a small beaker. Blow on it gently through a pointed
tube until evaporation is complete, or allow it to evaporate
spontaneously. What remains ?

Dry the black residue over a water bath and weigh with
the counterpoised filter.

Record and certify your results.

Character and per cent of the white .salt . . .

Character and per cent of the black residue . .

Character and per cent of the yellow substance

Read on the history and composition of gunpowder.

FILTRATION 3

Application to Quantitative Analysis of Soil. Thoroughly
dry about 5 g. of soil procured by the pupil. Weigh
exactly upon a balanced and folded filter paper. Place in
a funnel and wash with successive poi'tions of hot water
until the filtrate does not darken when heated with an
equal volume of concentrated H^SO^. Dry the filter paper
and contents at 100° C. Reweigh and calculate the loss of
weight as soluble matter. Transfer the dried residue to a
counterpoised porcelain or quartz crucible and determine
its exact weight. Gently heat to full redness with occa-
sional stirring, being careful not to lose any of the material.
Continue heating until all of the organic matter is burned
away. Cool the crucible in a desiccator and weigh the resi-
due. Calculate the loss as insoluble organic matter.

Tabulate as follows :

Soluble matter . . .... %

Insoluble organic matter %

Mineral matter . %

Total . 100%

How have you seen filtration employed outside of school ?

What is another name for the process ?

What kind of substances may be separated by filtration ?

Make a list of mixtures containing such substances.

Application to Commercial Analysis of Tea. The approxi-
mate value of tea may be determined by calculating the per
cent of matter which is not soluble in hot water. The in-
soluble matter should not be in excess of 60 per cent. If
over this amount, the presence of spent or exhausted leaves
is indicated.

Place exactly 2 g. of the finely powdered tea in a balanced
and folded filter paper. Extract with successive portions of
boiling water until the filtrate runs clear. Dry the residue

4 ELEMENTARY APPLIED CHEMISTRY

at 100° C. Cool and reweigh. Calculate by difference in
weight the per cent of water-soluble matter.

Test samples of tea of various prices, and answer the
question, Does the- price indicate the quality of tea based
upon matter insoluble in boiling water ?

What per cent of insoluble matter has the tea which is
used at your home ?

To isolate Theine, the Alkaloid of Tea. Extract a spoon-
ful of high-grade tea in 50 cc. of boiling water. Filter the
liquid and add 10 cc. of chloroform. Transfer the mixture
to a separatory funnel, shake the contents vigorously for a
minute, and allow the chloroform to settle. Draw it off
into a clean, dry watch glass and allow it to evaporate at
room temperature. Note the white, silky crystals and the
pleasant odor of the theine.

Repeat the above experiment, substituting coffee for
tea. The alkaloid of coffee is called what ? It is identicar
with that of tea. Its chemical symbol is CgHj^N^O^ + H^O.
What per cent of nitrogen does it contain ?

Application to a Domestic Analysis of Oysters. The de-
termination of the amount of water added to shucked oys-
ters is important from the viewpoint of the consumer. The
per cent of water that may be separated by means of a'
strainer or sieve should not exceed 15 per cent.i Weigh'
on a trip balance about a pint of the samplte as purchased.
Place in a flat-bottomed sieve and allow to drain into a
weighed dish for twenty minutes, stirring gently from time
to time. Determine the weight and per cent of the exterior
liquor. Determine the weight and per cent of the drained
oysters by difference.

1 Merck's RepoH, July, 1910, p. 189.

SECTION II,
ACIDS AND ALKALIS

Detection in Everyday Compounds. The instructor will
show samples of acids in solid, liquid, and gaseous form, to
do away with the impression that all acids are liquids.

Show samples of the common alkalis.

Discover the effect of acids and alkalis upon the vari-
ous indicators — phenolphthalein, methyl orange, cochineal,
carmine, and litmus.

Take home some litmus paper cut into small strips. Test
different articles — foods at the table, substances in the
kitchen, laundry, etc. Be sure that the substance tested, if
a solid, is either dissolved in water or well moistened.

One pupil tested the following : cream of tartar, ashes,
salt, milk, apple juice, borax, sugar, baking soda, washing
soda, soap, vinegar, tea, kerosene, tooth powder, coffee,
butter, stomach bitters.

Arrange your results in three columns, thus :

Acid Alkaline Neutral

Give the chemical names and symbols of as many of the
above list as possible. What per cent of the foods eaten
during the day were acid ? alkaline ? neutral ?

Determine the reaction of the soil from your lawn or
garden. What advantage is it to know this reaction ?

Thoroughly moisten 20 to 50 g. of the soil and in-
sert two pieces of litmus paper, one red, the other blue.

6 ELEMENTARY APPLIED CHEMISTEY

Allow them to remain undisturbed for an hour or even
overnight.

What would you suggest as a suitable dressing for an
aciel or " sour " soil ? for an alkaline one ?

What plants have a distinctly acid reaction ? Do you
know of any fruits which are not acid ? Find out the name
of the acid which imparts the sour taste to the common
sheep sorrel (^Rumex acetosella), apples, oranges, grapes,
rhubarb, etc. What acid is found in the membranous cov-
ering of nuts ? Mention some of the alkalis which are
found in nature.

SECTION III

ALKALIS IN TEXTILE AMAL^'SIS

Determination of the Per Cent of Wool and Cotton in
Fabrics. Wool is soluble in a solution of NaUlI or lv(.)Il.
C'otton is insoluble! in this reagent.

Qualitative Work. Place a small piece of the sample in
a test tube or crucible. Cover with 20 per cent K()1I

Fig. 1. Mixed goods heated with K<!)H, .sliowing cotton ix'widue

and boil for two or three minutes. If the sample en-
tirely dissolves, what is the per cent of wool ? Suppose it
partially dissolves, what is indicated ? Experiment with
bits of cotton, wool, and mixed goods until you are
familiar with the action of the caustic solution upon these
substances.

Caution. Take great care that none of the hot alkali
comes in contact with the flesh or clothing. If this does
hapjpen, apply dilute HCl at once.

8 ELEMENTARY APPLIED CHEMISTRY

Quantitative Work. If a portion of the cloth dissolves, cut
a second sample about 8 cm. square. Determine the exact
weight. Place in a beaker or large evaporating dish and
cover with the caustic potash. Boil for three minutes, or
until the wool is dissolved. Remove the cotton residue, tak-
ing care not to lose any detached threads. Rinse thoroughly.
Add a drop of phenolphthalein and sufficient HCl to make
slightly acid. Wash, dry at 100° C, and reweigh. Calcu-
late the per cent of wool and cotton. Devise a method for
testing silk.

SECTION IV

ACIDS AND ALKALIS IN THE QUALITATIVE
ANALYSIS OF SOILS

The appended list comprises the more important plant
foods, and the majority of them can be easily detected in
common soil.

Water Sulfuric acid as sulfates

Lime (CaCOg) Hydrochloric acid as chlorids

Carbon dioxid Nitric acid as nitrates

Ferric oxid (Fe^Gj) Magnesia (MgO)

Soda (Na^O) " Sand (SiOj)
Potash (KgO)

Calcium Carbonate. Place 10 g. of the soil in a test
tube and add 2 cc. of HCl. An effervescence indicates the
presence of a carbonate. This effervescence may frequently
be heard when the action is only faintly visible, by placing
the ear near the mouth of the test tube.

Add enough water to make a thin paste and boil for about
two minutes. Make alkaline with ammonia, and filter. Test
the clear filtrate with an equal volume of (Jl^H^')JOfi^. A
cloudiness or flocculent precipitate, which forms on standing,
indicates the presence of calcium.

CaCO, + 2 HCl = ?
CaCl, + (NHJ,Cp,= ?

Ferric Oxid. First Test. Boil 4 g. of the soil with 10 cc.
of HCl (5 parts of acid and an equal volume of water).
Filter and test half of the filtrate with ammonia added in

10 ELEMENTAEY APPLIED CHEMISTRY

excess. A reddish-brown, flocculent precipitate assures the
presence of iron in the sample of soil.

Second Test. To the other half of the filtrate add a few
drops of potassium sulfo-cyanide (KCNS). A blood-red
color is seen if ferric oxid is present in the original soil.
Test further by adding a little HgCl^ to a cubic centimeter
of the red liquid. The color should be destroyed. Write the
reactions which take place in the first and second tests.

Soda and Potash. Boil 50 g. of the soil in an equal
volume of water, stirring constantly. Allow the undis-
solved matter to settle and decant the clear liquid. Evapo-
rate this, preferably over a water bath, to about 5 cc. Clean
a platinum wire by heating until it gives no color to the
blue Bunsen flame. Dip the wire into the concentrated
filtrate and place immediately in the outer flame. A yellow
coloration indicates soda. A lilac or violet color, best seen
through a piece of cobalt-blue glass, indicates potash.

Sulfuric Acid as Sulfates. To a little BaCl^ solution add
a few drops of the filtrate left from the soda and potash
experiment. Boil. A precipitate insoluble in acids indi-
cates the presence of sulfates. Write the reaction between
sodium sulfate and barium chlorid.

Hydrochloric Acid as Chlorids. To two or three cubic
centimeters of the soda filtrate add a few drops of AgNOg.
Churn the contents of the test tube. A white, curdy precipi-
tate soluble in ammonia indicates the presence of chlorids
in the soil.

Since other substances are lUtely to precipitate the silver
solution, decant or filter off the ammoniacal solution and add
an excess of HCl. If a second precipitate is seen or a decided
milkiness is evident, the presence of chlorids is assured.
NaCl -f- AgNO, = ?

A(;ir)S AND ALKALIS

Nitric Acid as Nitrates. To one volume of Uiu soda-
potash filtrate add two volume.s of .strong H,S(J^ free l'r<jni
nitrates. Allow the mixture to cool. Incline the test tube
and cautiously add a few drops of a cijncentrated solution
of FeSO^, so that the li(iuids will not mix. A brownish
ring at the junction of the two
solutions assures the presence
of nitrates.

Phosphoric Acid as Phos-
phates. T<j 5 ec. of the soda-
potash liltrate add a few drops
of annu(]uuim nK.ilytjdate in
I1N(J^. Warm the evaporating
dish gently. The presence of
phosphates is indicated by a
lemon-yellow color, or, if there
is a considerable quantity pres-
ent, b}' a yellow precipitate.

Magnesia (MgO). 15oil 25 g.
of the soil in 50 cc. of \\'ater and
10 cc. of IK'l. Filter and evap-
orate the liltrate to aljout 5 cc.
Add a few drops of NH^C'l and

an equal volume of NlipH. j,,,, 2. Soil before and afturboil-
If a precipitate forms, filter and in^ in stvoiii;- HCl. Tlie i-esidue
test the filtrate with HNa^PO^. '" "'""'^

A white crystalline precipitate of ^IgNH^PO^, soluble in
acids, assures the presence of magnesium in the soil.

Sand. W

"■. o:

f the soil in a 250-cc. beaker with

a small stream of water, stirring constantly until all the
humus is washed out. Boil the residue in strong HCU
for five minutes. Sand is the princi^jal substance left.

12 ELEMENTARY APPLIED CHEMISTRY

Examine with a magnifying glass. What material do you
recognize? Can you suggest what some of the original
rock might have been ? How could you make this experi-
ment quantitative ?

Another important constituent of soils is organic nitro-
gen. Its detection and determination should be omitted
until the pupil is familiar with the Gunning method for
nitrogen, q.v.

SECTION V

DETECTION OF SOME OF THE COMPOUNDS
PRESENT IN PLANTS

By far the greater part of the growing plant is carbon
and water. How could you prove this ?

This list comprises other compounds present in plants
and vegetable matter.

Organic nitrogen

Chlorophyl

Starch

Phosphates

Sulfates

Chlorids

Potash and soda

Iron

Manganese (infrequently)

Silica

Organic Nitrogen. Grind a small handful of grass or
hay through a meat chopper. Mix with an equal weight
of soda lime or with strong KOH, and heat gently in an
Erlenmeyer flask, in the mouth of which is suspended a
strip of moist red litmus paper. The ammonia given off
will turn the test paper blue and prove the presence of
organic nitrogen.

Chlorophyl. Chlorophyl is the green coloring matter
common to growing plants.

Grind a handful of grass or green leaves, or scrape the
green layer from any woody stem. Triturate in a mortar
with enough alcohol to cover the mass. Decant or filter
the green liquid. Allow the alcohol to evaporate spon-
taneously. The chlorophyl remains as an intensely green

substance.

14 ELEMENTARY APPLIED CHEMISTRY

When extracted from suitable kinds of leaves, as spinach,
parsley, etc., the chlorophyl is sometimes used for color-
ing confections; jellies, and beverages. Of what use is
chlorophyl to plants?

Starch. Grind a few kernels of corn or any kind of
grain ; scrape a potato, or bruise any kind of root. Boil
with 10 cc. of water. Cool the contents of the tube and
add a few drops of iodin. A distinct blue coloration is
proof of the presence of starch.

Potash and Soda. First Test. Place a handful of dried
grass in a white enameled pan or upon a porcelain tile.
Light it with a blazing splint.. When it has stopped burn-
ing collect the residue in a porcelain crucible. Repeat the
experiment several times until the crucible is half full.
Heat until the contents are thoroughly ashed. Sometimes
the ash will be greenish, due to the presence Of manganese,
but more frequently it will be white or light brown. Care
must be exercised lest the ash fuse to the crucible.

Wash the ash into a beaker and boil in 25 cc. of water.
Allow the undissolved material to settle, and reserve. Ex-
amine the clear liquid directly for potash and soda by the
flame test, as directed for the analysis of soils. If the results
are not positive, evaporate 10 cc. of the liquid to dryness
and repeat the test. Is the liquid acid or alkaline ?

Second Test. Cut the bottom from a quart bottle or use
a glass percolator. Loosely plug the neck of the percolator
with absorbent cotton. Fill about two thirds full of sifted
wood ashes, through which allow half a liter of warm water
to pass. Collect the filtrate in a large evaporating dish or
enameled pan. Evaporate to dryness, but do not char. The
grayish-white substance is potash and soda, or the " lye "
used in the early settlements for making soft soap. Dissolve

COMPOUNDS PRESENT IN PLANTS 15

in a little water and treat with phenolphthalein, cochineal,
or litmus. Apply the flame test.

Phosphates, Sulfates, and Chlorids. Separate the unused
portion of the liquid obtained in the first or second test
into three parts and apply the appropriate tests, as directed
under soil analysis.

Iron. Boil the residue saved from the undissolved ash
with a few cubic centimeters of HCl. Decant the liquid
and test for iron with KCNS.

Silica. The residue from the iron test is mainly silica.
Wash with water, allow to settle, decant the liquid, and
rub the grayish material with the rounded end of a glass
rod. A distinct scratching sound can usually be heard.

Tabulate those exercises in which you have used an acid
or an alkali as a reagent. In which of these tests have you
found an acid or an alkali ?

SECTION VI

EXERCISES WITH STANDAED SOLUTIONS

Titration and Standard Solutions. The strength of many
solutions may be determined with great accuracy by adding
definite volumes of other solutions of known strength, which
will react chemically with them. The process is known as
titration, and is of great importance in chemical analysis.

The added solution is called a standard solution. It is
made to contain an accurately determined weight of chemical
substance in a definite volume.

A standard solution which contains 1 g. of replaceable
hydrogen per liter is known as a normal solution. Standard
solutions may be spoken of in terms of normal solutions, as
1/2, 1/10, 1/50, etc., usually written N/2, N/10, N/50.

The amount of a given substance to be dissolved in dis-
tilled water and made up to a liter will vary directly as its
molecular weight and inversely as the number of replace-
able hydrogen atoms represented in its molecule. Thus a
liter of normal HCl must contain 36.5 g. of acid, since its
molecular weight is 36.5 and only one atom of replaceable
hydrogen is present. A decinormal solution of this acid
will contain 3.65 g. per liter, while a cubic centimeter will
contain 0.00365 g.

A liter of normal H^SO^ must contain 49 g. of acid,
since its molecular weight is 98, and 2 atoms of replace-
able hydrogen are present. N/10 H^SO^ will contain 4.9 g.
per liter.

EXERCISES WITH STANDARD SOLUTIONS 17

A liter of normal oxalic acid (H^C^O^ + 2 H^O) must
contain 63 g. of acid, since its molecular weight is 126 and
it contains 2 atoms of replaceable hydrogen.

To prepare a liter of N/10 oxalic acid, weigh exactly
6.3 g. of acid of the highest purity, which has not lost its
water of crystallization, and transfer to a liter measuring
flask. Add about 500 cc. distilled water and agitate to dis-
solve the acid. This done, make up to the mark on the
neck with more distilled water. Turn into a clean, dry
bottle and mix thoroughly.

A cubic centimeter of any normal acid will exactly neu-
tralize a cubic centimeter of any normal allcali. A liter of
normal NaOH must contain 40 g. of the hydrate, since its
molecular weight is 40. A liter of normal KOH must con-
tain 56 g. of the salt because its molecular weight is 56.

That one may know when enough of a standard solution
has been added to neutralize or to complete the reaction, it
is customary to employ a third or neutral substance called
an indicator. Litmus, phenolphthalein, cochineal, methyl
orange, potassium chromate, etc. are often used.

Phenolphthalein is a good general indicator, but must
not be employed when more than traces of CO^ are present.
To prepare, dissolve 1 g. of the crystals in 100 cc. of 95 per
cent alcohol. To use, add two or three drops of the alco-
holic solution to the acid or to the alkaline solution under
examination. In acid or in neutral solutions phenolphthal-
ein is colorless, but the smallest excess of alkali turns it a
vivid purple-red.

To prepare a liter of N/10 NaOH, weigh roughly 4 g.
of the pure hydrate, transfer to a liter flask, and make up
to the liter mark with distilled water. When the hydrate has
dissolved, transfer to a large bottle and mix thoroughly.

ELEMENTARY APPLIED CHEMISTRY

The solution must now be standardized by the N/10 oxaHc
acid previously made.

By means of an accurate pipette transfer 10 cc. of the
NaOH solution to a beaker. Add two or three drops of
phenolphthalein. Set the beaker on a white
tile or sheet of white p^per and draw into it
from a burette just enough N/10 oxalic acid
so that the last drop destroys the lingering
trace of 'pink in the alkali. Note carefully
the amount of acid required.

Suppose 12 cc. are used; the alkali is too
strong, for 1 cc. of the acid must neutral-
ize 1 cc. of the alkali. Add 50 cc. of dis-
tilled water to the NaOH solution, mix well,
and again titrate 10 cc. By observing the
change made by the 50 cc. of water one
may easily calculate the amount of
water necessary to bring the alkaline
solution to the exact tenth-normal
strength.

Suppose only 8 cc. of the acid are
required to neutralize the solution ;
the NaOH is too weak. Add a drop
of saturated NaOH solution, mix well,
and titrate a second 10-cc. portion.
The requisite amount of alkali to be
added may be calculated. Thus by
adding water or alkali as required, an exact balance may
be secured. Work for perfect standardization.^

Fig. 3. A convenient
type of burette

1 For those wishing to go more into detail with volumetric solu-
tions, Olsen's "Quantitative Analysis" (D. Van Nostrand Co.) will be
helpful.

EXERCISES WITH STANDARD SOLUTIONS 19
A cubic centimeter of N/10 NaOH is equal to

Acetic acid (HC^HgOj) . .

0.0060 g.

Boric acid (HgBOj)

0.0062 g.

Citric acid (IIjCeHjO,, H^O)

. .0070 g.

Lactic acid (HCgHjOg) . . .

0.0090 g.

Malic acid (C^HeOj) .

. . 0.0067 g.

Oxalic acid (H^CgO^, 2 H^O)

0.0063 g.

Sulfuric acid (H2SO4) ....

. 0.0049 g.

Tartaric acid (H^C^H^O J

. 0.0188 g.

Determine the Acidity of Oranges or Lemons calculated
as Citric Acid. Weigh or counterpoise a small, clean, dry
evaporating dish. In this place 2 to 3 g. of orange juice
free from pulp. If lemon juice is used, 1.5 to 2 g. is suffi-
cient. Add two or three drops of phenolphthalein (^plie-
nolphtJtalein, 1 g.; alcohol, 100 cc.'). Fill a burette to the zero
mark with N/10 NaOH or talce any other convenient mark
as zero. Allow this standard solution to drop slowly into
the fruit juice until the first permanent trace of pmk appears
in the well-mixed solution. If, after standing for a minute,
the pinlc color disappears, add another drop of the alkali.
The fruit juice has been titrated with N/10 alkali.

Calculation
1 cc. of N/10 NaOH is equivalent to 0.007 g. of citric acid.

Suppose the weight of the orange juice and evaporating

dish is ... . 15.82 g.

Suppose the weight of the evaporating dish is . 13.30

Weight of the orange juice is . 2.52 g.

Suppose at the end of the reaction the burette reads . 13.80 cc.

Suppose the zero point was .... 10.50

Number of cubic centimeters of N/10 NaOH used 3.3 cc.

3.3 X .007 = .0231 g. of citric acid in the 2.52 g. of juice. There-
fore citric acid is present to the extent of 0.916 per cent.

20 ELEMENTARY APPLIED CHEMISTRY

Test the acidity of commercial lime and lemon juices.
The U.S.P. requires about 7 per cent of citric acid.

Determine the Purity of Cream of Tartar. Place exactly
half a gram of the sample in a clean beaker and dissolve
in boiling water. Add the phenolphthalein solution as in the
preceding experiment and titrate with decinormal NaOH.
After the first pink color appears, heat nearly to boiling.
If the color disappears, add another drop of the alkali.
Half a gram of pure cream of tartar requires approximately
26.6 cc. (26.595) of N/10 NaOH to neutralize it.

If your balance is suiSciently accurate, weigh exactly
0.188 g. Dissolve in hot water and titrate, using phenol-
phthalein. If pure, it will require 10 cc. of the N/10 alkali.

Determine the Purity of Baking Soda. Every cubic cen-
timeter of N/10 baking soda must contain .0084 g. of
HNaCOg. Why?

Titrate exactly half a gram of the sample with N/10 HCl,
using methyl orange as an indicator.

How many cubic centimeters were required ? Suppose the
sample were absolutely pure, how many cubic centimeters
of the N/10 acid would be required to neutralize it ?

What is the per cent of purity ? Write the reaction
between HCl and HNaCO^.

Determine the Per Cent of Lactic Acid in Milk. Fresh
milk should not contain over .2 per cent of acid. Cream
for the best butter should coiitaui from .5 to .65 per cent.

Into a clean white evaporating dish or teacup place 9 cc.
of milk or cream, being sure to rinse the graduate into
the cup. Titrate with N/10 NaOH, using phenolphthalein
as an indicator. Stir the contents of the cup frequently
with a glass rod. The rod must not be taken from the
dish lest some of the contents be lost. Neither must alkali

EXERCISES WITH STANDARD SOLUTIONS 21

from the burette spatter upon it. The first permanent tint
of pink in the milk indicates the end of the operation. The
color should remain pink after one minute.

The number of cubic centimeters of the standard alkali
used, indicates directly in tenths of one per cent the amount
of acid present. Thus :

6 cc. of the alkali = .6 per cent of acid.
9.3 cc. of alkali = .93 per cent of acid.

An Exercise in testing Vinegar. " Vinegar is formed by the
action of an organism found in the 'mother' of vinegar upon
weak alcoholic solutions.
This organism serves in
some way to carry the
oxygen of the air to the
alcohol. The sour taste is
largely due to acetic acid "
(^RemseTi).

The following equations
illustrate the process of so-
called acetic fermentation :
CJ-I„0+0=C,Hp+Hp.

alcohol

C,H,0+0 = HC,H30,

acetic acid

The physical and chemi-
cal examination of vinegar
is full of interest. Examine a few drops under a low-
power microscope and see if you can find any of the so-
called " vinegar eels." They are best seen after allowing
a large test tube of vinegar to remain undisturbed for
several hours. The eels are usually near the surface of
the liquid.

Fig. 4. "' Vinegar eels." (Magnified)
(Wilson)

22 ELEMENTAKY APPLIED CHEMISTEY

Total Acidity. Introduce exactly 6 cc. of the sample into
a clean beaker and set upon a white paper or tile in a good
light. Titrate with N/10 NaOH, using phenolphthalein as
an indicator.

The number of cubic centimeters of the decinormal alkali
used, divided by 10, represents the per cent of acetic acid.

Calculation

Suppose 34.3 cc. of the standard alkali are required to neutralize

34.3
6 cc. of the vinegar ; then — — = 8.43 per cent of acetic acid.

Proof. 1 cc. of N/10 NaOH neutralizes 0.006 g. of acetic acid.

34.3 X .006 = 0.2053 g. of acetic acid.

Therefore 6 g. (or 6 cc.)of vinegar contain 3.43 per cent of acetic acid.

The acidity of pure cider vinegar should not be less
than 4.5 per cent.

Total Solids. Weigh exactly 10 g. of the vinegar into a
tared crucible or evaporating dish and evaporate to dryness
for two hours. Cool in a desiccator, weigh, and calculate
the per cent of the residue. The total solids should not fall
below 2 per cent by weight if the sample is cider vinegar.

Ash. Place the vessel containing the total solids on a
suitable triangle and burn to ash at a low red heat. Cool
and weigh.

The ash should not be less than 0.25 per cent. Its reac-
tion to litmus should be distinctly alkaline. If it is not,
it contains some mineral acid which must be determined.
Gather some of the ash on the loop of a clean platinum
wire and apply the flame test. View through the cobalt-
blue glass if necessary. What base is present ?

Add a few drops of 10 per cent HCl. What radical
is evident? In the ash of pure cider vinegar potassium
carbonate is prominent.

EXERCISES WITH STANDAED SOLUTIONS 23

Ashby's Test for Mineral Acids. Prepare a solution of log-
wood by dissolving 0.5 g. of the extract in 100 cc. of boiling
water. Place one drop of this solution on the bottom of an
evaporating dish and dry over a water bath. To the dried
residue add a drop of vinegar and dry again. Pure vinegar
gives a yellow stain. Free mineral acids color the residue red.

To be sure of the Ashby reaction, it is well to add a
little H,SO^ to vinegar of known purity and compare the
result with the residue under examination.

To detect Sulfuric Acid in the Presence of Natural Sulfates
of the Vinegar. Evaporate 100 cc. of the sample to one tenth
of its volume, and when cold add 50 cc. of alcohol. Sulfuric
acid remains in solution while the natural sulfates are pre-
cipitated. Dilute the solution and precipitate the H^SO^
with BaClg. Write the reaction.

Detection of Caramel. Caramel, or burned sugar, is some-
times used to make the vinegar seem stronger than it really
is, or to make it resemble cider vinegar. Shake 5 cc. of the
sample with twice its volume of amyl alcohol. If caramel
is present, the supernatant layer will be wholly or par-
tially decolorized. The under layer will be a deep brown,
depending upon the amount of caramel present.

Detection of Coal-Tar Dye. Use the double-dyeing process
of Sostegni and Carpentieri, q.v.

To distinguish Cider Vinegar from Other Vinegars. Lyth-
goe's Method. Prepare lead subacetate solution by dissolv-
ing 180 g. of lead acetate in half a liter of water. A'dd
110 g. of PbO and make up to 1000 g. with water. Agitate
often and filter.

To 25 cc. of the vinegar add 2.5 co. of the subacetate
solution. Shake the contents of the tube. The precipitate
should be copious and settle out in a few minutes.

ele:mextaey applied chemistey

For comparative results, centrifuge in a graduated tube
and read the volume of the precipitate. The amount
piresent, in part at least, indicates the value of the vinegar.
Unless a precipitate is formed the
sample is not cider vinegar.

Determination of the Approximate
Acidity or Alkalinity of Soils. Boil
exactly 10 g. of thoroughly dried
soil m 30 cc. of water. Filter and
wash the residue several times with
small portions of liot water. Add the
washings to the filtrate with two or
three drops of phenolphthalem. If
the reaction is alkaline, titrate with
N/10 oxalic acid until the pink color
is destroyed by addition of the last
di-op.

If the reaction is acid, titrate with
N/lONaOH until the irrst tmge of
pink appears.

In either case express the result
as the number of cubic centimeters of
the N/10 solution required to neu-
tralize the filtrate.

Approximation of the Purity of
Cocoa. The purity of cocoa can, m
part at least, be determined by cal-
culating the per cent of its ash, \\liich in pure samples
seldom exceeds 5..5 per cent; and under ordinary condi-
tions the ash from each gram of the sample will require
not more than 3.7 cc. of N/10 oxalic acid to neutralize it.
If possible, test samples from your home.

Fig. 5. True and artifi-
cial vinegar treated with
lead subacetate

The artiticial vinegar, on

the right, sliows little or

no effect

EXERCISES WITH STANDARD SOLUTIONS 25

Burn 2 g. of the sample to a carbon-free ash at the
lowest possible heat. Cool the crucible and calculate the
per cent of ash. Boil the contents of the crucible in 50 cc.
of water, being sure to rinse it well and save the washings.
Titrate with N/10 oxalic acid, using phenolphthalein as
an indicator.

Analysis of Soap. Insoluble Matter. Dissolve 5 g. of the
sample in 75 cc- of water, heating if necessary. If there
are more than mere traces of residue, filter on a tared filter
paper, wash with hot water until the filtrate is neutral, dry
at 105° C, and calculate the per cent.

Test various " hand " and scouring soaps for insoluble
matter.

Alkali may exist in soap in at least three forms, — free,
combmed, and as alkaline carbonates, borates, etc.

Detection of Free Alkali. Treat the freshly cut surface
of the soap with a few drops of the alcoholic solution of
phenolphthalein. If no red color appears, it may be assumed
that free alkali is absent. Take great care that no water
comes in contact with the soap, otherwise the results may
be misleading.

When testmg washing powders for free alkali, dissolve a
small quantity in alcohol and add the phenolphthalein.

Combined Alkali. If free alkali, alkaline carbonates, bo-
rates, etc. are absent, dissolve a gram of the soap in 20 cc.
of hot water. Treat with phenolphthalein. A red color is
immediately seen. Why ?

Titrate with N/10 oxalic acid. Allow the acid to drop
slowly from the burette until the last drop added destroys the
pink color. Shake or stir the solution frequently during the
operation and be sure to waste none. If after a minute
the pink color reappears, add another di'op of the acid.

26 ELEMENTARY APPLIED CHEMISTKY

Free alkali may also be estimated by dissolving it
from 1 g. of the soap by means of alcohol. Filter, wash
with alcohol, and titrate as for combined alkali. Calcu-
late as NaOH.

Calculation fob Free or Combined Alkali

1 cc. of N/10 oxalic acid neutralizes Ice. of N/10 NaOH, or 0.004 g.
of NaOH. Suppose the number of cubic centimeters of acid required
is 4.75 ; then the per cent of alkali present is 4.75 x .004 = .019,
or 1.9 per cent.

Write the reaction between oxalic acid and sodium
hydrate.

Total Alkali. If the soap is free from sand and other
mineral matters, burn 2 g. to ash in a porcelain or quartz
crucible. Cool and wash the contents into 50 cc. of water.
Boil and titrate with N/10 oxalic acid, using two drops
of methyl orange as an indicator. (^Dissolve 1 g. of methyl
orange in 1 liter of water.')

Express the result as the acid number ; that is, the num-
ber of cubic centimeters of decinormal acid necessary to
neutralize the alkali in 1 g. of the soap.

Alkaline Carbonates. Place 5 g. of the soap in an Erlen-
meyer flask and add 20 cc. of alcohol. Set a funnel in the
neck of the flask to act as a reflux condenser, and heat on a
water bath for ten minutes. Alkaline carbonates will be in
the residue. Place a bit of this residue on a clean platinum
wire and apply the flame test for sodium and potassium
(see under Soil Analysis). Filter the alcohol and dis-
solve the residue in warm water. Add a few drops of
dilute HCl. A marked effervescence indicates the presence
of carbonates ; whether Na^COg (washuig soda) or K CO
(potash) will be indicated by the flame test.

EXEKCISES WITH STANDARD SOLUTIONS 27

Borates. Place 5cc. of turmeric tincture in a watch
glass. Add a few drops of the soap dissolved in water, and
acidify slightly with dilute HCl. Evaporate to dryness over
a water bath. The presence of borates is indicated by the
pronounced reddening of the dried residue.

Record the results of your analysis in this form :

Sa.iu'le

Pek Cext

Insoluble

Matter

Per Cent
Free Alkali

Per Cent

Combined

Alkali

Carbonates

SECTION VII

SANITARY AJSTALYSIS OF WATER

The importance of wholesome water cannot be overesti-
mated. Do the barns, the sinks, the outbuildings, contami-
nate the supply ? Does the water dissolve poisonous metals
from the pipes or other sources ? Is the water hard or soft ?
All these questions we shall be able to answer.

Clear, sparkling, odorless water may be totally unfit for
domestic purposes, while a suspicious-looking or peculiar-
smellmg sample may be quite harmless. A simple chemical
analysis is often of great value, except in the detection
of specific disease germs, when an intelligent bacteriologi-
cal examination is necessary. The analysis in this case,
however, may throw much light upon the source of the
contamination.

Keep carefully tabulated results of your analyses. You
can then see at a glance how the water varies from the
normal.

Sediment. Allow a test tube or conical glass full of the
water to stand overnight, or centrifuge 10 cc. in a pointed
tube. If any sediment falls, decant the liquid and exam-
ine the deposit under a microscope. This deposit may be
divided into two classes, harmless and suspicious matter:
harmless matter, sand, clay, alga, diatoms; suspicious matter,
hair, epithelial scales, bits of wool and cotton, muscle fibers, etc.

Filter the remainder of the original sample before making
further tests.

SANITAKY AIv^ALVSlS OF WATER

Color. Fill a clean test tube, the longer tlie better, with
the water, or use a Nessler tube. Stand it on a while
paper or tile, facing a good light. Cover the back of the
tube, except an inch at the Ijottoni, ^v•ith a piece of white
paper. On looking clown through the tube the water should
lie perfectly transparent, or show only a faint bluish tinge.
Pollution is indicated by tints
of green, yellow, or brown.

Odor. Warm about 250 cc.
of tlie water to 3S° C. in a
corked flask. Shake, remove
the stopper, and smell the con-
tents. Pure water is free from
cidor. The udor may be classi-
Ked as earthy, vegetable, alka-
line, putrid, etc.

^V putrid iidor indicates de-
composing animal or vegetable
matter. Jf nuicli polluted by
fresh sew age, the odor of urine
is )i(it infre(pient. One should
note that many waters unfit to
drink liave ikj odor. A positive
odor teaches volumes ; a nega-
tive result is of little value.

Total Solids. These C(aisist
for the most part of Oat'O^,, ]MgS(.)^, CaSO^ with their
chlorids and nitrates, NaC'l, Si(J„, and organic matter.

Evaporate 70 ce. of the water t<> dryness in a thin,
counterpoised evaporating dish over a water or steam bath.
Dry, cool in a desiccator, and weigh as milligrams. Every
milligram of solids per 70 cc. represents (.me grain per gallon

Fig. 6. A convenient rack for
Nessler tubes

The mu\'aljle mirror showy at an
an^le

ELEMEXTAEY APPLIED CHEMISTRY

in the oi'iguial sample. Total solids in good water may be
as liigii as 30 grains per gallon.

Save the residue and examine for phosphates. The resi-
due from pure water is almost white. Iron gives a yellow

or coppeiy luster to the sides
of the dish.

Evaporate about 50 cc. of
the sample in a porcelain
evaporating dish and heat
gently at first. Charring de-
notes the piresenee of organic
matter.

Determination of Chlorin.
Pleasure 50 cc. of the M-ater
with a }iipcttc into eacli of
two small llasks nr fieakers.
Add three or four drops
of potassium chromate solu-
tion, 10 per cent, as an indi-
cator, coloring the contents
of each flask exactly alike.
Place botli llasks on a wliite
tile in a good light. Titrate
the water in one of the flasks
with a standard silver solu-
tion. Do not add more than a drop at a time. Continue
the titration \\ith frequent agitation of the contents until
tlie water shows the first tinge of red. The first trace is
Ijest seen Ijy looking at the titrated sample through the
colored water in the control flask.

The number of cubic centimeters of tlie silver solution
re(|uired to produce the red tinge equals the number of

Fig. 7. Apparatus for the ileteinii

nation of chlorin in water

Control tlask on the left

SANITARY ANALYSIS OF WATER 31

parts of chlorin in 100,000 parts of water. If the water
contains more than five parts of chlorin per 100,000, con-
tamination from human urine or sink drains is to be sus-
pected, unless the water is taken near the seacoast or from
some locality where the normal sodium chlorid content
is above this amount. This information can usually be
obtained from any state board of health.

"Write the reaction between silver nitrate and potassium
chromate.

The standard silver solution is prepared by dissolving 2.3944 g. of
pure AgNOg in a liter of distilled water. Keep this solution in a
yellow or black bottle away from the light.

Detection of Ammonia. To 25 cc. of the water in a Nessler
tube, tall test tube, or foot tube, add 5 cc. of Nessler's
reagent and note the color. A faint yellow tinge only
should be visible. A deeper color or turbidity indicates
animal contamination.

Compare the treated water with an equal volume of the
untreated sample in a similar tube.

The experiment may be made quantitative by comparing
the color of the sample with different Nesslerized samples of
distilled water which contain known quantities of NH^Cl.

All natural waters contain a trace of ammonia, but the
amount present should not be sufficient to cause more than
a slight coloration with the Nessler solution. An excep-
tion must be made in the case of rain water, which, although
relatively pure, contains a considerable amount of ammonia
dissolved from the atmosphere. Rain water, however, shows
practically no nitrates or chlorin.

Nessler's Reagent. Dissolve 62.5 g. of KI in 250 cc. of water. Re-
serve about 10 cc. of this solution. Run into the remainder a cold,
saturated solution of HgCl., until a permanent precipitate forms.

32 ELEMENTARY APPLIED CHEMISTRY

Redissolve this precipitate by means of the reserve KI solution.
Very cautiously add more of the mercuric chlorid solution until a
slight preciijitate remains after agitation. Add 150 g. of KOH in
water and make up to a liter.

Allow the precipitate to settle and decant or siphon off the clear
liquid. This solution improves with age.

Detection of Nitrites. Into a Nessler tube place a drop of
HCl, 2 CO. of sulfanilic acid, an equal volume of naphthyl-
amine hydrochlorid, and 50 cc. of the water under exami-
nation. If a red color is produced immediately or within
twenty minutes, the presence of iiitrites is assured.

As a rule nitrites are never found in good water.

Sulfanilic Solution. Dissolve 0.8 g. of the acid in 100 ec. of pure
water, heating if necessary.

Naphthylamine Hydrochlorid Solution. Dissolve 0.8 g. of the salt
in 100 cc. of hot water to which 1 cc. of HCl has been added. Filter
through bone black or add bone black to the solution, and decant as
needed. Keep from the light.

Detection of Nitrates. Evaporate 100 cc. of the sample
to dryness in a white evaporating dish over a water or
steam bath. Treat with 1 cc. of phenol-sulfonic acid, stir-
ring thoroughly. Add 10 cc. of distilled water and half
as much Nil OH.

In the presence of nitrates the characteristic yellow color
of the ammonia salt of nitrophenol-sulfonic acid is formed.

Nitrates are present in almost all natural terrestrial waters.

Detection of Phosphates. Evaporate 70 cc. of the sample
to dryness or use the residue from the determination of total
solids. Add a few drops of ammonia molybdate in nitric
acid and warm gently. There should be only a slight lemon-
yellow coloration. A decided yellow coloration indicates
animal pollution. The degree of intensity is sometimes
recorded as traces, heavy traces, and very heavy traces.

SANITARY ANALYSIS OP WATER 33

Ammonium Molybdate Solution. Dissolve 15 g. of ammonium inolyb-
date in 100 cc. of water, with the addition of a little ammonia if neces-
sary. If there is pronounced turbidity, filter the solution and pour with
constant stirring into a mixture of 50 cc. nitric acid and an equal vol-
ume of water. Allow the solution to stand in a warm place for several
days at a temperature of about 80° F. and decant the clear liquid.

Determination of Absorbed Oxygen. This test gives
reliable information concerning the amount of organic
contamination, but does not distinguish between that of
animal and vegetable origin.

If more than one grain per gallon is absorbed, the water
is probably polluted.

Preliminary Test. Fill two test tubes half full, one with
distilled water, the other with the sample. To each add a
drop of strong H^SO^ and sufficient KMnO^ in distilled
water to color each a very light purple, as nearly alike
as possible. Boil the contents of each tube. What is the
action of organic matter on KMnO^ ?

Regular Test. Prepare a standard solution of KMnO^,
0.395 g. per liter, and keep in a clean well-stoppered bottle.

Place exactly 70 cc. of the water to be examined in a
clean flask and add ten drops of 10 per cent H^SO^. Warm
gently and add the standard solution from a burette, drop
by drop, shaking the flask gently after the addition of each
drop. As soon as the faintest tinge of pink appears, warm
the flask again and notice whether the color is permanent.
If not, add another drop. The first permanent tinge of pink
indicates the end of the operation.

Limit the test to fifteen minutes. Use an ordinary Bohe-
mian flask.

When 70 cc. of water is thus titrated, each cubic centi-
meter of the permanganate solution represents 0.1 of a grain
per gallon. Good water absorbs less than a grain per gallon.

34 ELEMEXTAEY APPLIED CHEMISTRY

Metallic Compounds. Lead. Evaporate 100 cc. of the
sample to 20 cc. and add a few drops of K.^Cr^O,. A pre-
cipitate of chrome yellow assures the presence of lead.

Iron and Copper. Boil 2 g. of stearic acid for five minutes
in 30 cc. of the suspected water. Set aside, and when
cool compare its color with a sample of the acid that has
been boiled for the same length of time in distilled water.
Examine before a white background. Iron salts impart a
yellow color. If traces of copper are present, the acid will
be colored a bluish green, which can be seen even before
the acid has solidified.

Hardness. Titrate 100 cc. of the water with N/10 HCl,
using methyl orange or erythrosin as an indicator. The
number of cubic centimeters of the decinormal acid used,
multiplied by 50, represents the number of parts of CaCOj
per million parts of water. Calculate the results to parts
per 100,000. Water is considered "hard" if it contains
over five parts of CaCO^ per 100,000.

SECTION VIII

EXAMINATION OF BAKING POWDER

All baking powders leave a more or less insoluble resi-
due in the food which they are used to leaven. What salts
does one take into his system when he eats cake or biscuit
made with cream of tartar, with alum, or with phosphate
baking powder ? The following reactions are of interest :

KiKD OF Baking

POWDEK

Reactions

Cream of tartar

HKCJ-I^Oj + HNaCOj = KNaCJI^O^, + CO^ + TT.O

PotaBemm bitartrate Rochelle saltB

Alum ....

KjAl^iSO^)^ + 6 HNaCOg = Al2(0H)5 + 3Na„S(),

Burnt alum Glauber's salts

+ K2SO4 + 6 CO,

Phosphate . .

H^CaCPO^)^ + 2 HNaCOj = HCaPO^ + HNaP(\

Calcium acid ^ 2 CO, + 2 II.,0
phosphate ' 2 ' 2

Determination of Carbon Dioxid. The value of a baking
powder, in part at least, depends upon the amount of avail-
able COj it contains. To determine this, two separate tests
are necessary.

Total Carbon Dioxid. This determination consists of lib-
erating the COj from a weighed amount of the sample,
passing the gas through caustic potash, and ascertaining
the increase in weight. Into an Erlenmeyer flask of about
150 cc. capacity weigh exactly 2 g. of baking powder.
Fit the flask with a dropping funnel and a delivery tube
inclined upward at an angle of about 20°. To the free

ELE.MEXI'AEV APPLIED CHE:MISTRY

end nf tlie delivery tul:)e attach a drying tnhe filled with
granulated C'aC'l,, previously saturated with C<;).,.

Fill a set of Liebig potash Ijulbs two thirds full of a
solution of 1 part KOH and 2 parts water. Determine
the exact weiglit of the prepiared Ijulbs l)y suspending from

Img. 8. Appanitiis for the lU'tenninatii.ii (i{ carbon dioxid

one arm of the ))a]ance. Tliis done, connect the inlet of the
bulbs with the free end of tlie drying tube, and the outer
end with an aspirator.

Fill the dropping funnel half full of IIC'l (sp. gr. 1.1).

Place a small drying tube filled with soda lime in the
mouth of tlie funnel, to prevent any CO,, from the air

EXAMINATION OF BAKING POWDER 37

being drawn into the potash bulbs when the aspirator is
in operation.

Open the funnel slightly and allow the acid to drop slowly
upon the sample. Adjust the aspirator so that the gas will
be drawn through the potash bulbs at the rate of about two
bubbles per second. When nearly all the acid has been
added, heat the contents of the generating flask to boiling,
until the water begins to condense in the delivery tube.

Aspirate until the potash bulbs are cool ; then discon-
nect and reweigh. The increased weight is due to total
carbon dioxid.

Write the reaction between HCl and baking soda. Is the
absorption of CO^ by KOH due to physical or chemical
change ?

Residual Carbon Dioxid. Thoroughly clean the apparatus
used in the determination of total carbon dioxid. Intro-
duce 2 g. of the sample into the generating flask and add
20 cc. of cold water. Allow it to stand for twenty minutes.
Then set the flask into a tin can surrounded by boiling
water for the same length of time. Drive off the last traces
of gas in the pasty mixture by boiling for one minute.
Aspirate until the air is thoroughly changed. At this
point in the experiment connect the apparatus and perform
the work exactly as for the determination of total carbon
dioxid. The increase of weight in the potash bulbs is due
to the residual carbon dioxid.

Available Carbon Dioxid. From the per cent of total carbon
dioxid subtract the p^ cent of residual carbon dioxid.

The average per cent of available carbon dioxid found in
the three principal kinds of baking powder is as follows :
cream of tartar, 12.58; phosphate, 12.86 ; alum, 8.10 (^Bulle-
tin No. 13, United States Bureau of Chemistry').

38 ELEMENTARY APPLIED CHEMISTRY

Tests for Radicals found in Baking Powder. CMorids.

Shake 2 to 4 g. of the sample with 25 cc. of cold water.
Filter. This constitutes a cold-water extract. To 5 cc. of
this extract add a few drops of 10 per cent AgNO^ solu-
tion. If a precipitate forms, agitate and allow it to settle.
If it is insoluble in hot water, but dissolves in ammonia,
the presence of chlorids is indicated.

AgN03 + XCl = ? AgCl + NH^OH = ?

Sulfates. Treat a few^ cubic centimeters of the cold-water
extract with barium chlorid solution. A precipitate insolu-
ble in acids and m water assures the presence of sulfates.

XSO^ + BaCl^ = ?

Tartrates. Dissolve a crystal of silver nitrate in 5 cc. of
water and add two drops of ammonia. Add 1 cc. of the
cold-water extract and heat gently. If tartrates are present,
the silver will be deposited as a beautiful silver mirror on
the interior of the tube.

Carbonates. To a gram or so of the dry baking powder
in a test tube add a few drops of dilute HCl. Hold a gkiss
rod wet with limewater so that the escaping gas will come
in contact with it. If the limewater becomes milky, the
presence of a carbonate is assured.

Write the reaction between hydi-ochloric acid and bicar-
bonate of soda. Write the reaction between carbon dioxid
and limewater.

Phosphates. Add a few drops of tlie cold-water extract to
a cubic centimeter of ammonium molvbdate (NH ) MoO^ in
HNOg. Heat gently. A lemon-yellow precipitate indicates
the presence of phosphates.

Phosphoric acid is an important constituent of the body.
Its presence can be easily demonstrated by experiment.

EXAMINATION OF BAKING POWDER 39

Burn a piece of bone in a clear fire until the residue is
perfectly white. Powder from 2 to 3 g. of this and dissolve
in HCl. Dilute the solution about one half and add an ex-
cess of ammonia. A white, gelatinous precipitate of calcium
and magnesium phosphate forms. Filter, and to the filtrate
add ammonium oxalate. The characteristic precipitate of
CaC„0, is evident.

What other radical was present in the bone ?

Tests for Bases found in Baking Powder. Calcium. To a
test tube half full of the extract add a few drops of ammo-
nium oxalate (J^H^yjufi^. A precipitate insoluble in acetic
acid, but soluble in hydrochloric acid, shows the presence
of calcium.

Write the reaction between ammonium oxalate and cal-
cium acid phosphate.

Ammonia. Boil 50 cc. of the extract with 25 cc. of 10 per
cent NaOH. Test the steam with red litmus jjaper. Avoid
touching the neck of the flask with the paper. If present,
the liberated ammonia will turn the test paper blue.

Write the reaction between ammonium carbonate and
sodium hydrate.

Aluminium. ( Thirty-first Report of the Massachusetts State
Board of Health.') Burn to ash about 2 g. of the baking pow-
der in a crucible. Extract with boiling water, and filter.
To the filtrate add sufficient NH^^Cl to give a distinct odor
of ammonia. A flocculent precipitate indicates the presence
of aluminium. The lower grades of baking powder often
contain salts of aluminium or of ammonium.

Detection of Alum in Pastry as well as in Baking Powder.
Make a tincture of logwood by digesting 5 g. of the well-
powdered chips in 100 cc. of alcohol. Prepare a saturated
solution of (NHJ^CO^.

40 ELEMENTARY APPLIED CHEMISTEY

Rub 5 g. of the baking powder, cake, cooky, or biscuit
in a mortar with 10 cc. of water. Add 2 cc. of the logwood
mixture and an equal volume of the ammonium carbonate
solution.

If alum is present, the color changes to lavender or blue,
and does not disappear on boiling. If alum is not present,
the color varies from red to pink.

SECTION IX

ANALYSIS OF MILK

More disease and fraud eiitei' the liome tlirougli the milk
supply than througli any (jthei' article of food. Chemistry
is of untold benefit in protecting peo[)le fr(jm these evils.

What is the quality and condition of the milk which you
are using at liome?

Fat. Examine a drop of milk under a half-inch objective
and note the collection of various-sized fat globules. De-
scribe their appearance and arrangement. Tlie fat of milk is

'% %•%

■% *li -%

Prom CLEAN MILK

From DIRTY M ILK

COTTON PLUGS F

"om

FILTERED MILK

Fi(i. '.)

one of its most variable constituents, and the determination
of the amount present is of importance.

Determination of the Per Cent of Fat by the Babcock
Method. This method consists in adding strong sulfuric acid
to the milk to dissolve all of the solids except the fat, which
is afterwards separated by means of a centrifugal macliine.

Measure exactly 1 7.6 cc. of tlie milk into a Babc/ock bottle
by means of a milk pipette. Add exactly 17.5 cc. of H ,SO^,

elemkxtai;y applied che^iistey

specific gnnity 1.83 at (i<)° F.. inclining tlic Ijottle so that
tlie acvl Avill niu in slowly and wash all adhering milk
from tlie neck.

Sliake ^yitll a rotary motion so as to thoronghlv mix
the acid and milk. Avciid getting cnrds into the neck
of the hottle.

If the A'iork has been done properly, the mixture •^'ill Ijc
a dark lirown color and very hot. Place directly into a
centrifuge, arranging the bottle so that the rotating head

Fig. 10. Haml and electric centrifujjes for milk analysis or for
sedimentation

will lialance properly. If the machine yibrates badly, the
Ijalance is not correct, and it must be adjusted.

Centrifuge for five minutes; then set the bottle into a
pan of hot water and add sufficient hot \\"ater to bring the
fat up to the neck of the Ijottle.

Centrifirge for two minutes and add hot water .sufficient
to bring the fat iippositc the graduated scale.

Centrifuge for one ininnte and take tlie reading in tenths
of 1 per cent directly from the srale.

.V [lair of small di\'iilers is us(.d'ul for determining the
length of the fat column. This dctermuicd, place one leg of

ANALYSIS OF MILK

the dividers upon zcio and take the reading from the oppo-
site leg. It is eustomar_y to taki; the distanee from the
bottom of the fat column t<j the top of its meniscus as
the true length.

The fat in milk varies from 2.2 per cent to 9.0 per
cent. The United States standard is 3.25 per cent. What
is the standard in your
state ?

Determination of Acid-
ity. Test both with red
and blue litnuis paper.
1 'erfectly fresh ct )w"s milk
is generally alkaline. It
is sometimes amphoteric,
that is, it exliil)its the
phenomenon of reacting
alkaline with red litmus
and acid with blue. The
acidity increases as the
milk sugar is converted
into lactic acid.

For quantitative deter-
mination of lactic acid,
see page 20.

Specific Gravity. De-
termhie with a lactometer, speciirc-gravity flask, or West-
plial balance. Milk of good standard quality slunild have
a specific gravity of 1.027-1.033 at 00° F.

Milk whose specific gravity varies from these limits is
of a suspicious character.

Total Solids, by Evaporation. Heat 2 g. of milk to a con-
stant weight in a counterp(jised dish over a, water bath.

Fig. 11. Babcock Ijottles for milk and
cream with dividei'M to f acilitatt; reading

44:

ELE-^LEXTAl;Y APPLIED CHE.MISTKY

The residue cif milk must not Ije heated
over 100° C, as it will decompose and
lose weight almost indefinitely. If prop-
erly heated, the dried residue will be almost
white.

Total Solids, by Richmond's Slide Rule.
This method is Ijy far the more conven-
ient, and accurate enough for all practical
purposes.

Take the temperature of the milk and
the lactometer reading. Set this reading on
tile slide opposite the observed temperature.
The corrected reading will be found oppo-
site 60 on the scale. Call this reading A.

Place the arrow at the riglit-haud end of
tlie slide, o[)posite the per cent "f fat found
by the Babeock method. Find A on the
opposite edge of the slide. It will coincide
with the total solids in tlie milk.

The results obtained by these two methods
should agree closely.

Total solids sliould not be less than 12.50
pier cent.

Tests for Foreign Matter, Dirt, Hair, etc.
Some of the most disagreeable as \\-ell as
dangerous kinds of foreign matter A\hich
contaminate the milk supply enter tlu-ough
the carelessness of the pn'odneer.

Construct a percolator by cutting the bot-
tiim from a pint bottle, or use an ordinar\"
glass percolator employed by a druggist.
Insert a plug of clean absorbent cotton in

ANATA'WIS (_>F MILK

the neclv from the inside, and allow a half pint or more of
the well-shaken milk to slowly filter through. Remove the
plug carefully and examine (see p. 41).

Insoluble matter, if present, can easily be seen. Wash
the clean end oi the plug gently with cold water. Dry and
mount on cardboard with an appro-
priate inscription.

Tests for Adulterants : Artificial
Colors. Coloring matter is sorae-
tiines added to milk to give it a
rich, creamy apjieaiance. The prac-
tice, if not absolutely injui'ious, is
at least reprehensible. Wliy?

The two most connnonl^y em-
ployed coloi'S ai-e annatto and coal-
tar dye.

Detection of Annatto. Shake
al)out .5 cc. of the milk «ith t«ice
its volume of ether in a large test
tube. When the li(|uid.s have sepa-
rated, pour off the ether extract.
Evaporate on a water bath. ]\'Iake
the residue alkaline with NaOIi
and pour on a small wet iilter
paper. The annatto will be ab-
sorbed by the pores of the paper.

Wash off the fat gently with slightly warmed water.
Annatto will trive a decided orange tone, which turns to
pink when treated with a few drops of stannous chlorid.

Detection of Coal-Tar Dye. To 10 cc. of the milk add
an equal volume of IICl and mix thoroughly. A pink
coloration uulicates the presence of azo orange.

Fic;. 13. Percolating milk,

for dirt and other foreign

matter

46 ELEMENTARY APPLIED CHEMISTRY

Tests for Adulterants : Preservatives. The preservatives
most commonly employed to keep milk sweet for a longer
time than nature intended are formaldehyde, compounds
of boron (horax and boric acid'), sodium bicarbonate, and
calcium sucrate.

Detection of Formaldehyde (HCHO). This is one of the
most poisonous of preservatives found in foods, and when
so used cannot be too strongly condemned.

Leach's Casein Test. First Part. To 10 cc. of pure milk
add an equal volume of hydrochloric acid, contaming about
1 per cent of Fe^Clg. Use an evaporating dish or casserole
and heat slowly, stkring or shaking the contents constantly
to break up the curd. When nearly but not quite boiling,
remove the heat and note the color of the treated milk when
hot and when cold.

Second Part. To 50 cc. of water add 1 cc. of HCHO
and mix the liquids well. Add two drops of this dilute
formaldehyde to 10 cc. of pure milk and perform the work
as directed under the first part.

How is the presence of formaldehyde indicated ? How
much was in the milk, assuming that the cubic centimeter
added to the water contamed 40 per cent formaldehyde ?

The work under the first and second parts is designed to
make the pupil familiar with the appearance of miUi which
contains and which does not contain formaldehyde, when
the samples are treated with hydrochloric acid containing
a small percentage of ferric chlorid.

To test any given sample of milk, proceed as directed
under the first part, and if the results are similar to those
obtained under the second part, the presence of formalde-
hyde is indicated. Both this and the following test are
exceedingly delicate and the results are thoroughly reliable.

ANALYSIS OF MILK 47

Detection of HCHO by means of Hehner's Ring. To 25 vol-
umes of H^SO^ add 1 volume of ferric chlorid solution.
Place 4 cc. of this reagent in a large test tvibe and carefully
add 5 ce. of the suspected milk, inclining the tube so that
the milk shall rest upon the surface of the acid. In the
presence of formaldehyde a violet rmg is seen at the contact
of the two liquids.

Detection of Boron Compounds. First Part. Place 5 cc. .
of pure milk in a watch glass and acidulate slightly with
10 per cent HCl. Add five drops of turmeric tincture and
evaporate to dryness over a water bath. What is the
appearance of ■ pure milk thus treated ?

Second Part. To 5 cc. of the milk add a drop of boric acid
or borax dissolved ui a little water. Transfer to a watch glass
and proceed as before. Take care that the mixture does not
char. How is boron mdicated ? The reaction is said to be
sensitive to 1 part of boric acid in 25,000 parts of milk. The
red color is proportionate to the amount of boron present.

Test unknown samples of milk, performmg the work as
outlined under the first part. If the sample of miUt is very
rich, or if cream is under examination, dilute with two or
three volumes of water.

Turmeric Tincture, U.S. P. Digest any convenient amount of
ground turmeric root in small quantities of water, discarding the
liquids. Digest the dried residue with six times its weight of alcohol,
and filter.

Detection of Bicarbonate of Soda. The ash of pure milk
shows no effervescence with HCl. Burn 10 cc. of milk to
a white ash in a porcelain or. quartz crucible over a low
flame. Treat the ash with a drop of 10 per cent HCl. An
effervescence indicates bicarbonate of sodiuin.

HNaCO, + 2 HCl = ?

48 ELEMENTAEY APPLIED CHEMISTRY

Detection of Calcium Sucrate. This substance is used as
a thickener as well as a preservative, and is more frequently
found in cream than in milk. It may be readily detected by
means of the Baier and Neumann test which follows :

First Part, the Sugar. To 25 cc. of the milk or cream add
10 cc. of a 5 per cent solution of uranium acetate. Shake
and allow to stand for five minutes.

Filter ; if the filtrate is not clear, pour it through again.
To 10 cc. of the clear filtrate (if the sample is cream,
use the total filtrate) add 2 cc. of a cold saturated solu-
tion of ammonium molybdate freshly prepared and 8 cc. of
dilute HCl (1 part of 25 per cent HCl and 8 parts of
water). Agitate the mixture well and place the small flask
containing it in a water bath at 80° C. for ten minutes.

If the sample is pure, the solution will be a peculiar
green, resembling nickel sulfate solution ; but if sugar is
present, it will be a Prussian blue color.

Second Part, the Calcium. Evaporate 25 cc. of the milk
or cream to dryness and burn to ash in a muffle. Dissolve
the ash in 20 cc. of N/10 H^SO^. Boil to expel the CO^ and
titrate back with N/10 NaOH, using plienolphthalein as
the indicator.

Express the results as cubic centimeters of N/10 acid re-
quired to neutralize 100 g. of milk or cream. Suppose that
the ash was dissolved in 20 ee. of N/10 acid and that 14 cc.
N/10 NaOH neutralized the excess. It is evident that 6 cc. of
the acid was required to neutralize the alkalinity of the ash.

Detection of Gelatin in Milk, Cream, and Ice Cream.
This substance is sometimes used in cream, and more
frequently in ice cream, either as a thickener or to make
the material stand transportation better. Gelatin is readily
detected by the Stokes test.

ANALYSIS OF MILK

Stokes's Test. To 10 cc. of the sample add an equal
volume of acid nitrate of mercury solution and 20 cc. of
cold water. Shake the mixture vigorously and allow it to
stand for five minutes. Filter; if gelatin is present, the
filtrate will be opalescent. Confirm by treating the filtrate
with 1 cc. of a saturated aqueous solution of picric acid.
The gelatin will be precipitated as a yellow solid, more or
less flocculent in appearance.

^Icid Nitrate of Mercury Solution. Dissolve any convenient weight
of mercliry in twice its weight of concentrated HNOg and dilute this
solution to 25 times its bulk with water.

Detection of Milk adulterated by Skimming and by
Watering. In order to do this work intelligently one must
become familiar with the principal factors employed in
calculations of this kind. These factors are:

Total solids : all the constituents of milk except water.

Fat.

Solids not fat : obtained by subtracting the fat content
from the total solids.

Proteins: the nitrogenous part of the milk.

Ash: the mineral constituents.

Milk sugar and lactose.

The following table, devised by H. C. Lythgoe, is believed
to show the limits between which normal milk varies :

Extreme limits

Usual limits

Herd milk

(per cent)

Total solids

10.0-17.0

10.5- 16.0

11.8-15.0

Fat

2.2 - 9.0

2.8- 7.0

3.2- 6.0

Proteins

2.1- 8.5

2.5- 4.5

2.5- 4.0

Ash

0.6- 0.9

0.7- 0.8

Solids not fat ... .

7.5-11.0

7.7-10.0

8.0- 9.5

Milk sugar . .

4.0- 6.0

4.2- 5.5

4.3- 5.3

50 ELEMENTARY APPLIED CHEMISTRY

A relation has been found to exist between the fat and
proteins of milk. If the fat is given, the proteins may be
approximately calculated by means of Van Slyke's formula :
0.4 (F.- 3) +2.8 = P.

Suppose the fat found in a certain sample of milk is
3.50 per cent. According to the formula, the proteins are
3.0 per cent.

A relation also exists between the total solids and
proteins, which is expressed by Olsen as
T.S.-T.S/1.34 = P.

Suppose the solids in the sample mentioned above were
12.50 per cent. The proteins, by Olsen's formula, are 3.18
per cent. If the milk is pure, the per cent of proteins calcu-
lated by the two formulas will agree closely with a variation
of approximately 0.2 per cent or less. If the milk is adulter-
ated with water or by skimming, the results will not agree,
the difference increasing with the amount of adulteration.

Illustrations. A sample of milk known to be watered contained
3.4 per cent fat and 10.41 per cent of total solids.

Proteins calculated from the fat 2.96%

Proteins calculated from the solids . . . 2.65 %

Difference . . .... . ^31%

A sample of milk known to be skimmed contained 2 per cent fat
and 11.18 per cent of total solids.

Proteins calculated from the fat . . 2.40%

Proteins calculated from the solids . . 2.84 %

Difference ■ -44%

According to Lythgoe we may use these formulas in the
indirect calculation of milk sugar, if we assume the average
ash of milk to be 0.7 per cent.

T.S. - (F. + [0.4 (F. - 3) + 2.8] + 0.7) = Milk sugar.
T.S. - (F. + [T.S. -T.S./1.34] + 0.7) = Milk sugar.

ANALYSIS OP MILK 51

Detection of Skimmed Milk. If the sample has been
skimmed, the calculated proteins will exceed the fat, and
the calculated milk sugar will be too high, exceeding 4.8
per cent, which is approximately the average milk sugar,
according to the table.

If the fat is less than 2.2 per cent and the solids not
fat are above 8.5 per cent, the milk has probably been
skimmed.

Detection of Added Water, Copper Sulfate Method. Since
there is no chemical test to distinguish between added
water and the water naturally present in milk, it is cus-
tomary to precipitate the fat and proteins by means of
acetic acid, copper sulfate, or by spontaneous souring. This
leaves the fat and protein in the curd, the milk sugar and
ash in the whey.

Dissolve 72.0 grains of pure orystaHized CiiSO^ in a little water
and dilute to 1 liter. Adjust this to have a specific gravity of 1.0443
at 20° C. compared with water at 4°C.

To 1 part of copper solution add 4 parts of sweet milk,
shake thoroughly, and filter.

If the speciiic gravity of the clear filtrate is less than
1.0245 at 20° C, compared with water at 4° C, added water
is indicated.

Dry 5 cc. of the copper serum to a constant weight over
a water bath. Determine the weight of the 5 cc. from the
specific gravity of the serum and calculate the total solids.
If the total solids are below 5.28 per cent, added water is
indicated.

SECTION X

EXAMINATION OF ICE CREAM, CHEESE, AND
CONDENSED MILK

Determination of the Fat in Ice Cream. Tare a Babcock
cream bottle and add 10 g. of the well-mixed sample
together with 5 or 6 cc. of water. Mix thoroughly and
add just enough suKuric acid to turn the contents dark
brown. Avoid an excess of acid, as the mixture will char
badly. Proceed with the regular Babcock test. Multiply
the scale reading by 18 and divide by 10, to find the per
cent of fat.

The per cent of fat m ordinary cream is also found by
this method.

Starch. Boil a small quantity of the sample in a test
tube with 10 cc. of water. Cool, and add a few drops of
iodin tincture. The well-known blue color will be evident
if the sample contains starch.

If starch is present, place a drop of the sample on a
slide and examine with the microscope to see if you can
determine the kind.

Gelatin. Apply Stokes's test.

Fat in Cheese. Weigh 6g. of the sample in a tared beaker.
Add 10 cc. of boiling water and a few drops of ammonia.
Stir gently until a smooth emulsion is formed. Transfer
the contents to a Babcock cream bottle, cool slightly, and
add 17.6 cc. of H^SO^, first rinsing out the beaker with the
acid. Proceed with the regular Babcock test.

ICE CEEAM, CHEESE, CONDENSED MILK 53

The fat reading on the scale multiplied by 18 and divided
by the weight of the sample (6 g.) gives the per cent of
fat in the cheese.

How can you distinguish a full-cream cheese from a
skimmed-milk cheese ?

Fat in Condensed Milk (Unsweetened). Weigh 6 g. of
the thoroughly mixed sample into a tared Babcock milk
bottle and add enough water to make the volume up to
about 17.6 cc. Mix, and add sufficient H^SO^ to produce the
deep brown color required by the Babcock method. About
14 cc. of acid will be needed. Proceed with the regular
Babcock test.

Multiply the fat reading by 3, to find the correct per
cent of fat in the sample.

Number of Times Condensed and Fat in the Original Milk.
The average ash of pure milk is .70 per cent. Burn from
2 to 3 g. of the sample in a crucible and calculate the per
cent of ash. This per cent divided by . 7 gives approximately
the number of times the milk has been condensed.

Divide the fat found by the Babcock method by the
number of times condensed, to find the fat in the original
sample.

SECTION XI

DISTILLATION EXPERIMENTS

Prepare a solution of 2 g. of NaCl in 50 cc. of water.
Taste. Add a few cloves and a little sand, and color with
red ink or dye. Pour into a retort or distilling Hask. Adjust
a suitable condenser and distil off about one half.

Examine both residue and distillate. What substances
are present in the distillate that were present in the original
mixture ? What kinds of substances are separated by distil-
lation ? What physical principle is involved ? What prac-
tical applications of distillation do you know of ? What is
fractional distillation ?

Extraction of Essential Oils. The odor and taste of many
ve_getable substances is due, in large measure, to the presence
of a volatile compound known as essential oil.

What is the difference. between fixed and essential oils?

Extract the essential oil from wintergreen leaves, sweet
birch (^Betula lentula), cloves, cinnamon, nutmeg, pepper-
mint, bay leaves, orange or lemon rind.

To obtain the greatest amount of oil from any of these
substances, grind tlu'ough a meat chopper, add water to
make an extremely thin paste, and distil. At first the dis-
tillate will be of a milky appearance, due to the suspended
oil. Set aside until the liquid clears.

A second method for the extraction of essential oils,
which gives even better results than the first and removes
the liability of breaking the retort through the heavy

DISTILLATION EXPERIMENTS 55

material sticking to the bottom, is to place the finely ground
mass in a dry flask fitted with a two-hole stopper and con-
nected with a condenser. Steam from a generating flask is
blown in through a long bent glass delivery tube, which
extends nearly to the bottom of the flask.

What is the use of essential oils ? What is the meaning
of " essence," " extract," and " tincture " ? How may essen-
tial oils be extracted except by distillation ? (See Harpers'
Monthly for November, 1906. )

Experiments with Alcohol. Few substances are of greater
industrial value than alcohol. Make a list of the uses of
alcohol, either ethyl (C^H^H) or methyl (CHpH), or
both. What is denatured alcohol ?

Usually from 5 to 8 per cent of grain alcohol is sufficient
to preserve the extractive principles of medicine. How do
you account for such high amounts as 28. to 44 per cent
sometimes present ?

Make a medicine tester. Cut a piece of quarter-inch
glass tubing 8 in. long. Smooth the ends. Push one end
through a one-hole rubber stopper. To the free end fit an
ordinary Welsbach burner and mantle.

Place two tablespoonfuls of the liquid under examina-
tion in a Bohemian flask and insert the stopper and tube.
Heat the flask gently, and if alcohol is present in amounts
of over 12 per cent, it will cause the mantle to glow brightly
when ignited.

To get the best effect, inclt)se the mantle in a glass or
mica chimney. Some brands of "bitters," "tonics," "cures,"
"specifics," etc. contain enough alcohol to keep up the
incandescence for five or six minutes.

Instead of the Bohemian flask one may substitute a cop-
per can fitted with a small screw stopper. Into the top of

ele:\iextai;y applied chemistry

the can solder a piece of gas pipe about 8 in. long and fit
with a Ijurner. Be sure that all connections are well made.

Fig. 14. Testing apparatus to demonstrate the presence of alcohol hi
medicine and beverages

Preparation of Alcohol (C^H^OH). Dissolve 30 g. of cane
sugar in 7o cc. of water, add a chop of HC'l, and boil one

DISTILLATION EXPERIMENTS 57

minute. If grape sugar or 20 cc. of molasses is used instead
of cane sugar, the boiling and acid may be omitted.

Dissolve half a cake of yeast in the same volume of water
not above 50° C. Cool the sugar solution to about the same
temperature and mix with the yeast. Allow to remain in a
warm place for two or three days, and observe from time to
time any visible changes.

Decant the liquid into a retort and distil off about one
half. Wash the retort, pour in the distillate, and distil off
10 cc. Test the second distillate as follows:

Determine its odor and taste. In it test the solubility
of a bit of camphor or the oil from a piece of orange or
lemon peel. Burn a little in an evaporating dish. To
equal quantities of the distillate and acetic acid add a few
drops of H^SO^, taking care that the contents of the tube
do not spatter in your face. Heat gently. Notice the
ethereal, fruitlike odor of ethyl acetate, or acetic ether, a
substance much used in the preparation of artificial flavor-
ing compounds.

If the experiment has been conducted properly, the fer-
mented liquid will contain about 4.5 per cent of alcohol
by volume.

Cane sugar does not ferment. Treated properly with
acid the reaction probably takes place as follows:

C,.H,p„ -f HP = C,H,p, + Gfl,p,.

cane sugar glucose fructose

CAA = 2C,HpH + ?

The instructor or one of the pupils should prepare a
flask of the sugar-yeast mixture. Fit a delivery tube so
that its free end dips below the surface of a few cubic cen-
timeters of limewater contained in a small, narrow-necked

58 ELEMENTAKY APPLIED CHEMISTRY

bottle. The presence of CO^, given off during the process
of fermentation, is thus easily demonstrated.^

Determination of the Per Cent of Alcohol by Distillation.
The chemical and physical characteristics of alcohol are so
apparent that a qualitative analysis is seldom necessary. It
is highly important, however, to know how much of this
substance enters into the composition of various medicines
and articles intended for internal use. To comply with the
Food and Drugs Act, the amount of alcohol must be plainly
stated upon the label. How does your analysis agree with
the statement ?

Introduce exactly 100 cc. of sweet cider, beer, wine, medi-
cine, root-beer extracts, or any of the various " tonics " and
" blood purifiers," into a retort and distil off about one half,
being sure that the free end of the condenser dips deeply
into the receiving flask. Make up the distillate to exactly
100 cc. by adding distilled water. Determine the specific
gravity of the thoroughly mixed distillate, and from this
determine the per cent of alcohol by volume by means of
the tables (pp. 66-75).

Repeat the experiment by weighing exactly 100 g. of
the sample in a tared flask or beaker. Transfer to a retort
and distil as before.

Make the distillate up to 100 g. with distilled water.
Take the specific gravity. From this determine, by means

1 The student will find helpful references to alcohol in the following
publications :

Popular Science Monthly: "History of Alcohol," Vol. LI, p. 231;
"Physiology of Alcohol," Vol. L, p. 796; "Natural Production of Alco-
hol," Vol. XIX, p. 238; "Discovery and Distillation of Alcohol," Vol.
XLIII, p. 85; "Use of Alcohol in Medicine," Vol. XXXVIII, p. 86;
"Vinous Superstitions," Vol. XXIV, p. 234; "Pigs as Wine Bibbers,"
Vol. XXIV, p. 426.

Farmers^ Bulletin No. S68, United States Department of Agriculture.

DISTILLATION EXPERIMENTS

01 the la))le.s, the per cent of alcohol hy weight. Discover
any mathematical sequence in the alcoliol tal)les(pp. (l(i-75).

Suggestions. Always carefnlly rinse the vessel contain-
ing the measured amount of the sample int(j the retort,
using al)out half its
volume of water.

Determine the tem-
perature of the dis-
tillate at wliich yon
take the specific
gra\'ity and correct
to 60° F. or 15° t'.
Fr)r all temperatures
ahove these stand-
ards sul)tract .OOOSO
for each Centigrade
degree or .0OUL4 for
eacli Fahrenheit de-
gree. For all temper-
atures l)elow these
standards tlie cor-'
rection is ad<litive.

If, fur this work,
pupils are encour-
aged to bring sam-
ples from home, the
results will often l)e
a revelation not only to themselves but also to their parents.

Determination of the Per Cent of Alcohol by Difference in
Specific Gravity. Tliis method, suggested hy Ijcacli, gives
approximate results. Use the preceding method whenever
possible.

Fif:. 15. Apparatus for dutorminiiii,' the
per I't'iit of alcoliiil

60 ELEMEXTAEY APPLIED CHEMISTRY

Determine the specific gravity of the original sample.
Evaporate 50 cc. over a water bath to one fourth its
bulk. Make up to its original volume with distilled water.
Determine the specific gravity of this dealcoholized por-
tion. Add 1 to the original specific gravity and subtract the
second. The difference corresponds to the alcohol in the
original sample.

Consult the tables (pp. 66-75) as before and read the
per cent of alcohol by volume.

Methyl or Wood Alcohol (CH3OH). . It is difficult to find a
more dangerous liquid used to cheapen food products and
medicinal preparations than methyl alcohol. It is responsi-
ble for many cases of death and blindness. It apparently
makes little difference whether it is taken internally in
medicines and beverages, rubbed on the skin as a liniment,
or its vapor inhaled; death, severe illness, or blindness
may result.^

In more instances than one this poison has been found,
in its deodorized form, in Jamaica ginger, lemon extract,
peppermint and cinnamon, "hot drops," liniments, bitters,
toilet waters, bay rum, witch hazel, spirits of camphor,
paregoric, whisky.

Detection of Methyl Alcohol. Except where a refractom-
eter is used, the presence of wood alcohol is proved indi-
rectly, usually by oxidizing it into formaldehyde.

Cut a piece of No. 14 copper wire 90 cm. long. At a
point 20 cm. from one end wind the wire neatly around a
pencil into a close spiral until about 20 cm. from the oppo-
site end. Push the first end through the coil and twist
both together to form a handle.

1 For instances of methyl alcohol poisoning, see Journal of the Ameri-
can Medical Association, October 1-29, 1904.

DISTILLATION EXPEEIMENTS 61

Prepare a solution of 1 part CHgOH and 6 parts water.
Mix, and pour 10 cc. into a 5-in. test tube whose inside
diameter is a little greater than the diameter of the spiral.
Stand the tube in a bottle of cold water, to cool the contents
during the oxidizing process.

Heat the coil to a dull red in the upper Bunsen flame
and plunge immediately into the dilute alcohol. Withdraw
in a second and dip into water. Repeat the operation from
three to six times. This treatment will change all or a
part of the alcohol into formaldehyde.

CHpH - 2 H = HCHO.

CuO + 2 H = ?

What reaction takes place when the copper spiral is
heated in the upper Bunsen flame ?

Decant the oxidized liquid and divide into two portions.
Add one portion to a little milk and apply the tests for
formaldehyde.

To the other portion add 1 drop of 1 per cent resorcin
solution and mix well. Pour this mixture carefully clown
the side of a wide test tube which contains a half inch of
concentrated H^SO^. A red ring (not brown) will form
between the two liquids. If much formaldehyde is present,
a precipitate may be seen. This is known as Hehner's
resorcin test.

Test witch hazel, lemon extract, cheap vanilla, etc.
by oxidizing 10 cc. as indicated. In the case of vanilla
it is advisable to distil off about 10 cc. and oxidize the
distillate.

Caution. One must always be sure that the original
sample does not contain formaldehyde before testing for
methyl alcohol, otherwise the results might be misleading.

ELE.MEXTAEY APPLIED CHEMISTEY

If there is a question, adil a few drops of the original
sample to 5 ec. of milk ami apply the Hehiier test.

jVll aldehydes may be removed by distilling 50 cc. of the
sample with 10 g. of sodium bisulfite and alknvhig the mix-
ture to stand for two hours. Distil a second time, and make

distinctly alkaline
withXaOH. Oxidize
this distillate and
test for methyl alco-
hol (Rvjhirt JIiis.s((-
cJiusetts State BoanJ
of Health, moo,
p. 401).

Use of Alcohol in
the Preparation of
Vanilla Extract. The
preparation of fla-
^■oring extracts from
pure and high-grade
materials is a \alu-
able ex[)erience for
students of chcm-
istrv. The work ean
be done in the lab-
oratory or at home.

Fn:. 10. Copper .■spiral ami water-cooleil test

tube for the oxiilation of methyl aleohol into

fonnaUlehvde

A'anilla extract is the flavtiring extract prepared from
vanilla beans, wdth or ^^dthcait sugar or glycerin, and con-
tains in 100 ce. the soluble matters from not less than
10 g. of the beans (f. S. »fa)i,]ard).

r reparatiun (United States FJiarmaeopeeia). Cut 100 g.
(if Aanilla licans in a meat chopper, -wliieh must be clean
and free from foreign odors. Weigh 2()0 g. of coarse

DISTILLATION EXPERIMENTS 63

granulated sugar; mix 650 cc. of alcohol with 350 cc. of
water.

Macerate the vanilla in 500 cc. of this dilute alcohol
for twelve hours ; then drain off the liquid and set it aside.
Transfer the vanilla to a mortar and beat it with the sugar.
Pack the mass into a "percolator, the neck of which has
been plugged with a piece of absorbent cotton from within,
and pour on the reserved dilute alcohol. When this has
disappeared from the surface, gradually pour on the men-
struum and continue percolation until 1000 cc. have been
obtained. E-epercolajte several times.

Vanilla extract improves with age. If the alcoholic mix-
ture remains on the beans for several months, the flavor of
the extract will be improved.

To distinguish between True and Artificial Vanilla Extract.
Many of the so-called vanilla extracts contain little or no
vanilla, but are composed of a dilute alcoholic solution of
vanillin, or coumarin, prepared from coal tar. Sometimes
true coumarin, the aromatic principle of the tonka or
" snuff " bean, is added to make the flavor more pronounced
and lasting. Such extracts are often colored with caramel
or with coal-tar dye.

Some experience is necessary to distinguish between true
and artificial extracts by a sense of smell or taste alone, but
there are several chemical tests which will definitely settle
the matter.

By the Lead Acetate Precipitate. To 40 cc. of the sample
add an equal volume of normal lead acetate solution pre-
pared by dissolving 189.5 g. of Fh(Cfip;)^+Sllfl in
water and diluting to 1 liter.

The absence of a precipitate is conclusive evidence that
the extract is artificial. Pure vanilla thus treated yields a

64 ELEMENTARY APPLIED CHEMISTRY

heavy precipitate wliich should settle in a few minutes,
leaving a clear, partially decolorized liquid (LeacK).

By Examination of the Resins Present. Evaporate the alco-
hol from 50 cc. of the extract over a water bath and
make up to the original volume with water. If an alkali
(usually KjCOg) has not been used in the manufacture of
the extract, the resins will appear as a flocculent red to
brown residue. Acidify with acetic acid, allow to stand for
a few mmutes, and collect the resins on a filter paper.
Wash the residue twice with slightly warmed water.

Tear off a portion of the filter p9,per with the resins
attached, and place it in a few cubic centimeters of dilute
KOH. If the vanilla is pure, this resm will dissolve, making
a deep red solution.

Dissolve the rest of the resin in alcohol and divide the
solution into three parts:

(a) Add a few drops of ferric chlorid. There will be no
particular change if the vanilla is pure.

(V) Add a few drops of dilute HCl. If the vanilla is
pure, there will be no particular color change.

(c) Add a few drops of lead subaeetate solution. If
the vanilla is pure, the precipitate will be so bulky as to
almost solidify. Its filtrate will be almost colorless (^Bulletin
No. 107, revised).

Use of Alcohol in the Preparation of Lemon Extract.
Lemon extract is the flavoring extract prepared from the oil
of lemon or from lemon peel, or both, and contains not less
than 5 per cent by volume of lemon oil ( U. S. standard).

An extract of fair quality, but which does not contain the
legal amount of lemon oil, may be prepared by grating the
yellow rind from six lemons and macerating in 40 per cent
alcohol for a few days. It can then be filtered and used.

DISTILLATION EXPERIMENTS 65

A legal extract can be prepared by dissolving 1 oz. of
lemon oil in 19 oz. of alcohol. This extract can then be
colored, if desired, by the addition of some of the bright
yellow solution prepared from the lemon peel.

Approximate Test for Strength and Purity. To 50 cc. of
cold water add 2 cc. of the lemon extract. The oil will be
thrown out of solution, giving the top of the water column a
decided milky appearance. The depth of the milkiness, in a
measure, enables one to judge of the strength of the extract.
Absence of the milky color is conclusive proof that the
extract is artificial. If it is of a decided yellow color, test
for artificial color as directed under Coal-Tar Dye.

Per Cent of Lemon Oil. Mitchell's Test. Place 20 cc. of
the extract in a Babcock milk bottle. Add 1 cc. dilute HCl
(1 to 1) and about 28 cc. of warm water at 60° C. Mix
and allow the bottle to stand in warm water at the same
temperature for five minutes. Centrifuge for five minutes.
Add warm water to bring the oil into the graduated neck.
Centrifuge for two minutes more and stand the bottle in
water at 60° C. up to the top of the oil column for a few
minutes, and read the per cent of oil by volume.

If more than 2 per cent of oil is present, add 0.4 per
cent to correct for the oil retained in solution. If between
1 and 2 per cent, add 0.3 per cent for correction.

ELEMENTARY APPLIED CHEMISTRY

TABLE FOR DETERMIXATIOX OF ALCOHOL PER-
CENTAGES 1

By Squibb, Drinkwater, and Gilpin

Alcohol

Specific
Gravity

AT|goF.

Alcohol i

Specific
Gravity

AT|g°F.

Alcohol

Specific

UUAVITY
AT|§OF.

Per
cent
by vol-
ume

Per

cent

weigbt

Per

cent
by vol-
ume

Per
cent
by

weight

Per
cent
by vol-
ume

Per
cent

by
weight

1.00000

0.00

0.99775

1..50

1.19

0.99557

3.00

2.39

0.99992

0.05

0.04

.99768

1.55

1.23

.99550

3.05

2.43

.99984

0.10

0.08

.99760

1.60

1.27

.99543

3.10

2.47

.99976

0.15

0.12

.997.53

1.65

1.31

.99.536

3.15

2..51

.99968

0.20

0.16

.99745

1.70

1.35

.99529

3.20

2.55

.99961

0.25

0.20

.99738

1.75

1.39

.99522

3.25

2.59

.99953

0.30

0.24

.99731

1.80

1.43

.99515

3.30

2.64

.99945

0.35

0.28

.99723

1.85

1.47

.99508

3.35

2.68

.99937

0.40

0.32

.99716

1.90

1..51

.99501

3.40

2.72

.99930

0.45

0.36

.99708

1.95

1.55

.99494

3.45

2.76

.9992.3

0.-50

0.40

.99701

2.00

1.59

.99487

3..50

2.80

.99915

0.55

0.44

.99604

2.05

1.63

.99480

3.55

2.84

.99907

0.60

0.48

.99687

2.10

1.67

.99473

3.60

2.88

.99900

0.05

0..52

.99679

2.15

1.71

.99466

3.65

2.92

.99892

0.70

0.56

.99672

2.20

1.75

.99459

3.70

2.96

.99884

0.75

0.60

.99665

2.25

1.79

.99452

3.75

3.00

.99877

0.80

0.64

.99658

2.30

1.83

.99445

3.80

3.04

.99869

0.85

0.67

.99651

2.35

1.87

.99438

3.85

3.08

.99861

0.90

0.71

.99643

2.40

1.91

.99431

3.90

3.12

.99854

0.95

0.75

.99636

2.45

1.95

.99424

3.95

3.16

.99849

1.00

0.79

.99629

2.50

1.99

.99417

4.00

3.20

.99842

1.05

0.83

.99622

2.55

2.03

.99410

4.05

3.24

.99834

1.10

0.87

.99615

2.60

2.07

.99403

4.10.

3.28

.99827

1.15

0.91

.99607

2.65

2.11

.99397

4.15

3.32

.99819

1.20

0.95

.99600

2.70

2.15

.99390

4.20

3.36

.99812

1.25

0.99

.99593

2.75

2.19

.99383

4.25

3.40

.99805

1..30

1.03

.99586

2.80

2.23

.99376

4.30

3.44

.99797

1.35

1.07

.99579

2.85

2.27

.99369

4.35

3.48

.99790

1.40

1.11

.99571

2.90

2.31

.99363

4.40

3.52

.99782

1.45

1.15

.9956^

2.95

2.. 35

.99356

4.45

3.56

1 From BuUetin No. 107, United States Department of Agriculture.

PERCENTAGE OF ALCOHOL

PERCENTAGE OF ALCOHOL (Continued)

Alcohol

Specific
Gravity

AT|8°F.

Alcohol

Specific
Gravity
AT IgoF.

Alcohol

Specific
Gravity

ATggoF.

Per

cent

by rol-

unie

P.er

cent

■weiglit

Per
cent
by vol-
ume

Per

cent

weight

Per
cent
by vol-
ume

Per

cent

weight

0.99349

4.50

3.60

0.99117

6.25

5.00

0.98897

8.00

6.42

.99342

4.55

3.64

.99111

6.30

5.05

.98891

8.05

6.46

.99335

4.60

3.68

.99104

6.35

5.09

.98885

8.10

6.50

.99329

4.65

3.72

.99098

6.40

5.13

-.98879

8.15

6.54

.99322

4.70

3.76

.99091

6.45

5.17

.98873

8.20

6.58

.99315

4.75

3.80

.99085

6.50

5.21

.98867

8.25

6.62

.99308

4.80

3.84

.99079

6.55

5.25

.98861

8.30

6.67

.99301

4.85

3.88

.99072

6.60

5.29

.98855

8.35

6.71

.99295

4.90

3.92

.99066

6.65

5.33

.98849

8.40

6.75

.99288

4.95

3.96

.99059

6.70

5.37

.98843

8.45

6.79

.09281

5.00

4.00

.99053

6.75

5.41

.98837

8.50

0.83

.99274

5.05

4.04

.99047

6.80

5.45

.98831

8.55

6.87

.99268

5.10

4.08

.99040

6.85

5.49

.98825

8.60

6.91

.99261

5.15

4.12

.99034

6.90

5.53

.98819

8.65

6.95

.99255

5.20

4.16

.99027

6.95

5.57

.98813

8.70

6.99

.99248

5.25

4.20

.99021

7.00

5.61

.98807

8.75

7.03

.99241

5.30

4.24

.99015

7.05

5.65

.98801

8.80

7.07

.99235

5.35

4.28

.99009

7.10

5.69

.98795

8.85

7.11

.99228

5.40

4.32

.99002

7.15

5.73

.98789

8.90

7.15

.99222

5.45

4.36

.98996

7.20

5.77

.98783

8.95

7.19

.99215

5.50

4.40

.98990

7.25

5.81

.98777

9.00

7.23

.99208

5.55

4.44

.98984

7.30

5.86

.98771

9.05

7.27

.99202

5.60

4.48

.98978

7.35

5.90

.98765

9.10

7.31

.99195

5.65

4.52

.98971

7.40

5.94

.98759

9.15

7.35

.99189

5.70

4.56

.98965

7.45

5.98

.98754

9.20

7.39

.99182

5.75

4.60

.98959

7.50

6.02

.98748

9.25

7.43

.99175

5.80

4.64

.98953

7.55

6.06

.98742

9.30

7.48

.99169

5.85

4.68

.98947

7.60

6.10

.98736

9.35

7.52

.99162

5.90

4.72

.98940

7.65

6.14

.98730

9.40

7.56

.99156

5.95

4.76

.98934

7.70

6.18

.98724

9.45

7.60

.99149

6.00

4.80

.98928

7.75

6.22

.98719

9.50

7.64

.99143

6.05

4.84

.98922

7.80

6.26

.98713

9.55

7.68

.99136

6.10

4.88

.98916'

7.85

6.30

.98707

9.60

7.72

.99130

6.15

4.92

.98909

7.90

6.34

.98701

9.65

7.76

.99123

6.20

4.96

.98903

7.95

6.38

.98695

9.70

7.80

ELEMENTARY APPLIED CHEMISTRY

PERCENTAGE OF ALCOHOL (Continded)

Alcohol

Specific
Gravity

AT §g°F.

Alcohol

Specific
Gravity
ATggoF.

Alcohol

Specific
Gravity

ATggoF.

Per

cent
by vol-
ume

Pel-
cent

weight

Per

cent
by vol-
ume

Per
cent

■weight

Per

cent
by vol-
ume

Per

cent

weight

0.98689

9.75

7.84

0.98491

11.50

9.27

0.98299

13.25

10.69

.98683

9.80

7.88

.98485

11.55

9.31

.98294

13.30

10.74

.98678

9.85

7.92

.98479

11.60

9.35

.98289

13.35

10.78

.98672

9.90

7.96

.98474

11.65

9.39

.98283

13.40

10.82

.98666

9.95

8.00

.98468

11.70

9.43

.98278

13.45

10.86

.98660

10.00

8.04

.98463

11.75

9.47

.98273

13.50

10.90

.98654

10.05

8.08

.98457

11.80

9.51

.98267

13.55

10.94

.98649

10.10

8.12

.98452

11.85

9.55

.98262

13.60

10.98

.98643

10.15

8.16

.98446

11.90

9.59

.98256

13.65

11.02

.98637

10.20

8.20

.98441

11.95

9.63

.98251

13.70

11.06

.98632

10.25

8.24

.98435

12.00

9.67

.98246

13.75

11.11

.98626

10.30

8.29

.98430

12.05

9.71

.98240

13.80

11.15

.98620

10.35

8.33

.98424

12.10

9.75

.98235

13.85

11.19

.98614

10.40

8.37

.98419

12.15

9.79

.98230

13.90

11.23

.98609

10.45

8.41

.98413

12.20

9.83

.98224-

13.95

11.27

.98603

10.50

8.45

.98408

12.25

9.87

.98219

14.00

11.31

.98597

10.55

8.49

.98402

12.30

9.92

.98214

14.05

11.35

.98592

10.60

8.53

.98397

12.35

9.96

.98209

14.10

11.39

.98586

10.65

8.57

.98391

12.40

10.00

.98203

14.15

11.43

.98580

10.70

8.61

.98386

12.45

10.04

.98198

.14.20

11.47

.98575

10.75

8.65

.98381

12.50

10.08

.98193

14.25

11.52

.98569

10.80

8.70

.98375

12.55

10.12

.98188

14.30

11.56

.98563

10.85

8.74

.98370

12.60

10.16

.98182

14.35

11.60

.98557

10.90

8.78

.98364

12.65

10.20

.98177

14.40

11.64

.98552

10.95

8.82

.98359

12.70

10.24

.98172

14.45

11.68

..98546

11.00

8.86

.98353

12.75

10.28

.98167

14.50

11.72

.98540

11.05

8.90

.98348

12.80

10.33

.98161

14.55

11.76

.98535

11.10

8.94

.98342

12.85

10.37

.98156

14.60

11.80

.98529

11.15

8.98

.98337

12.90

10.41

.98151

14.65

11.84

.98524

11.20

9.02

.98331

12.95

10.45

.98146

14.70

11.88

.98518

11.25

9.07

.98326

13.00

10.49

.98140

14.75

11.93

.98513

11.30

9.11

.98321

13.05

10.53

.98135

14.80

11.97

.98507

11.35

9.15

.98315

13.10

10.57

.98130

14.85

12.01

.98502

11.40

9.19

.98310

13.15

10.61

.98125

14.90

12.05

.98496

11.45

9.23

.98305

13.20

10.65

.98119

14.95

12.09

PERCENTAGE OF ALCOHOL

PERCENTAGE OF ALCOHOL (Continued)

Alcohol

Specific
Gravity

AT88°F.

Alcohol

Specific
Gravity
AT ggop.

Alcohol

Specific
Gravity

ATggoF.

Per

cent
by vol-
ume

Per

cent

weight

Per

cent
by vol-
ume

Per

cent

weight

Per

cent
by vol-
ume

Per

cent

weight

0.98114

15.00

12.13

0.97935

16.75

13.57

0.97758

18.50

15.02

.98108

15.05

12.17

.97929

16.80

13.62

.97753

18.55

15.06

.98104

15.10

12.21

.97924

16.85

13.66

.97748

18.60

15.10

.98099

15.15

12.25

.97919

16.90

13.70

.97743

18.65

15.14

.98093

15.20

12.29

.97914

16.95

13.74

.97738

18.70

15.18

.98088

15.25

12.33

.97909

17.00

13.78

.97733

18.75

15.22

.98083.

15.30

12.38

.97904

17.05

13.82

.97728

18.80

15.27

.98078

15.35

12.42

.97899

17.10

13.86

.97723

18.85

15.31

.98073

15.40

12.46

.97894

17.15

13.90

.97718

18.90

15.38

.98068

15.45

12.50

.97889

17.20

13.94

.97713

18.95

15.39

.98063

15.50

12.54

.97884

17.25

13.98

.97708

19.00

15.43

.98057

15.55

12.58

.97879

17.30

14.03

.97703

19.05

15.47

.98052

15.60

12.62

.97874

17.35

14.07

.97698

19.10

15.51

.98047

15.65

12.66

.97869

17.40

14.11

.97693

19.15

15.55

.98042

15.70

12.70

.97864

17.45

14.15

.97688

19.20

15.59

.98037

15.75

12.75

.97859

17.50

14.19

.97683

19.25

15.63

.980.32

15.80

12.79

.97853

17.55

14.23

.97678

19.30

15.68

.98026

15.85

12.83

.97848

17.60

14.27

.97673

19.35

15.72

.98021

15.90

12.87

.97843

17.65

14.31

.97668

19.40

15.76

.98016

15.95

12.91

.97838

17.70

14.35

.97663

19.45

15.80

.98011

16.00

12.95

.97833

17.75

14.40

.97658

19.50

15.84

.98005

16.05

12.99

.97828

17.80

14.44

.97653

19.55

15.88

.98001

16.10

13.03

.97823

17.85

14.48

.97648

19.60

15.93

.97996

16.15

13.08

.97818

17.90

14.52

.97643

19.65

15.97

.97991

16.20

13.12

.97813

17.95

14.56

.97638

19.70

16.01

.97986

16.25

13.16

.97808

18.00

14.60

.97633

19.75

16.05

.97980

16.30

13.20

.97803

18.05

14.64

.97628

19.80

16.09

.97975

16.35

13.24

.97798

18.10

14.68

.97623

19.85

16.14

.97970

16.40

13.29

.97793

18.15

14.73

.97618

19.90

16.18

.97965

16.45

13.33

.97788

18.20

14.77

.97613

19.95

16.22

.97960

16.50

13.37

.97783

18.25

14.81

.97608

20.00

16.26

.97955

16.55

13.41

.97778

18.30

14.85

.97603

20.05

16.30

.97950

16.60

13.45

.97773

18.35

14.89

.97598

20.10

16.34

.97945

16.65

13.49

.97768

18.40

14.94

.97593

20.15

16.38

.97940

16.70

13.58

.97763

18.45

14.98

.97588

20.20

16.42

ELEMENTARY APPLIED CHEMISTRY

PERCENTAGE OF ALCOHOL (Continued)

Alcohol

Specific
Gravity

Alcohol

Specific
Gravity

Alcohol

SPEcrFic
Gravity

Per

AT IgoF.

cent
by vol-

cent

ATlgoF.

cent
by vol-

cent

AT|8°F.

cent
by vol-

cent
by

ume

weight

ume

weight

ume

weight

0.97583

20.25

16.46

0.97406

22.00

17.92

0.97227

23.75

19.38

.97578

20.30

16.51

.97401

22.05

17.96

.97222

23.80

19.42

.97573

20.35

16.58

.97396

22.10

18.00

.97216

23.85

19.40

.97568

20.40

16.59

.97391

22.15

18.05

.97211

23.90

19.51

.97563

20.45

16.63

.97386

22.20

18.09

.97206

23.95

19.55

.97558

20.50

16.67

.97381

22.25

18.13

.97201

24.00

19.59

.97.5.52

20.55

16.71

.97375

22.30

18.17

.97196

24.05

19.63

.97547

20.60

16.75

.97370

22.35

18.21

.97191

24.10

19.67

.97542

20.65

16.80

.97365

22.40

18.26

.97185

24.15

19.72

.97537

20.70

16.84

.97360

22.45

18.30

.97180

24.20

19.70

.97532

20.75

16.88

.97355

22.50

18.34

.97175

24.25

19.80

.97527

20.80

16.92

.97350

22.55

18.38

.97170

24.30

19.84

.97.522

20.85

16.96

.97345

22.60

18.42

.97165

24.35

19.88

.97.517

20.90

17.01

.97340

22.65

18.47

.97159

24.40

19.93

.97512

20.95

17.05

.97335

22.70

18.51

.97154

24.45

19.97

.97507

21.00

17.09

.97330

22.75

18.55

.97149

24.50

20.01

.97502

21.05

17.13

.97324

22.80

18.59

.97144

24.55

20.05

.97497

21.10

17.17

.97319

22.85

18.63

.97139

24.60

20.09

.97492

21.15

17.22

.97314

22.90

18.68

.97133

24.65

20.14

.97487

21.20

17.26

.97309

22.95

18.72

.97128

24.70

20.18

.97482

21.25

17.30

.97304

23.00

18.76

.97123

24.75

20.22

.97477

21.30

17.34

.97299

23.05

18.80

.97118

24.80

20.26

.97472

21.35

17.38

.97294

23.10

18.84

.97113

24.85

20.30

.97467

21.40

17.43

.97289

23.15

18.88

.97107

24.90

20.35

.97462

21.45

17.47

.97283

23.20

18.92

.97102

24.95

20.39

.97457

21.50

17.51

.97278

23.25

18.96

.97097

25.00

20.43

.97451

21.55

17.55

.97273

23.30

19.01

.97092

25.05

20.47

.97446

21.60

17..59

.97268

23.35

19.05

.97086

25.10

20.51

.97441

21.65

17.63

.97263

23.40

19.09

.97081

25.15

20.56

.97436

21.70

17.67

.97258

23.45

19.13

.97076

25.20

20.60

.97431

21.75

17.71

.97253

23.50

19.17

.97071

25.25

20.64

.97426

21.80

17.76

.97247

23.55

19.21

.97065

25.30

20.68

.97421

21.85

17.80

.97242

23.60

19.25

.97060

25.35

20.72

.97416

21.90

17.84

.97237

23.65

19.30

.97055

25.40

20.77

.97411

21.95

17.88

.97232

23.70

19.34

.97049

25.45

20.81

PEECENTAGE OF ALCOHOL

PERCENTAGE OF ALCOHOL (Continued)

Alcohol

Specific
Gkavity

ATggoF.

Alcohol

Specific
Gravity

ATlg"!".

Alcohol

Specific
Gkavitv

ATig°F-

Per

cent
by vol-
ume

Per
cent

weight

Per
cent
by vol-
ume

Per

cent

weight

Per

cent
by vol-
ume

Per

cent

weight

0.97044

25.50

20.85

0.96855

27.25

22.33

0.96658

29.00

23.81

.97039

25.55

20.89

.96850

27.30

22.37

.96652

29.05

23.85

.97033

25.60

20.93

.96844

27.35

22.41

.96646

29.10

23.89

.97028

25.65

20.98

.96839

27.40

22.45

.96640

29.15

23.94

.97023

25.70

21.02

.96833

27.45

22.50

.96635

29.20

23.98

.97018

25.75

21.06

.96828

27.50

22.54

.96629

29.25

24.02

.97012

25.80

21.10

.96822

27.55

22.58

.96623

29.30

24.06

.97007

25.85

21.14

.96816

27.60

22.62

.96617

29.35

24.10

.97001

25.90

21.19

.96811

27.65

22.67

.96611

29.40

24.15

.96996

25.95

21.23

.96805

27.70

22.71

.96605

29.45

24.19

.96991

26.00

21.27

.96800

27.75

22.75

.96600

29.50

24.23

.96986

26.05

21.31

.96794

27.80

22.79

.96594

29.55

24.27

.96980

26.10

21.35

.96789

27.85

22.83

.96587

29.60

24.32

.96975

26.15

21.40

.96783

27.90

22.88

.96582

29.65

24.36

.96969

26.20

21.44

.96778

27.95

22.92

.96576

29.70

24.40

.96964

26.25

21.48

.96772

28.00

22.96

.96570

29.75

24.45

.96959

26.30

21.52

.96766

28.05

23.00

.96564

29.80

24.49

.96953

26.35

21.56

.96761

28.10

23.04

.96559

29.85

24.53

.96949

26.40

21.61

.96755

28.15

23.09

.96553

29.90

24.57

.96942

26.45

21.65

.96749

28.20

23.13

.96547

29.95

24.62

.96937

26.50

21.69

.96744

28.25

23.17

.96541

30.00

24.66

.96932

26.55

21.73

.96738

28.30

23.21

.96535

30.05

24.70

.96926

26.60

21.77

.96732

28.35

23.25

.96529

30.10

24.74

.96921

26.65

21.82

.96726

28.40

23.30

.96523

30.15

24.79

.96915

26.70

21.86

.96721

28.45

23.34

.96517

30.20

24.83

.96910

26.75

21.90

.96715

28.50

23.38

.96511

30.25

24.87

.96905

26.80

21.94

.96709

28.55

23.42

.96505

30.30

24.91

.96899

26.85

21.98

.96704

28.60

23.47

.96499

30.35

24.95

.96894

26.90

22.03

.96698

28.65

23.51

.96493

30.40

25.00

.96888

26.95

22.07

.96692

28.70

23.55

.96487

30.45

25.04

.96883

27.00

22.11

.96687

28.75

23.60

.96481

30.50

25.08

.96877

27.05

22.15

.96681

28.80

23.64

.96475

30.55

25.12

.96872

27.10

22.20

.96675

28.85

23.68

.96469

30.60

25.17

.96866

27.15

22.24

.96669

28.90

23.72

.96463

30.65

25.21

.96861

27.20

22.28

.96664

28.95

23.77

.96457

30.70

25.25

ELEMENTARY APPLIED CHEMISTRY

PERCENTAGE OF ALCOHOL (Continued)

Alcohol

Specific
Gravity

AT|goF.

Alcohol

Specific
Gravity

AT|8°F.

Alcohol

Specific
Gravity

ATfgOF.

Per
cent
by vol-
ume

Per

cent

weight

Per
cent
by vol-
ume

Per

cent

weight

Per
cent
by vol-
ume

Per

cent

weight

0.96451

30.75

25.30

0.96235

32.50

26.80

0.96010

34.25

28.31

.96445

30.80

25.34

.96229

32.55

26.84

.96003

34.30

28.35

.96439

30.85

25.38

.96222

32.60

26.89

.95996

34.35

28.39

.96433

30.90

25.42

.96216

32.65

26.93

.95990

34.40

28.43

.96427

30.95

25.47

.96210

32.70

26.97

.95983

34.45

28.48

.96421

31.00

25.51

.96204

32.75

27.02

.9.5977

34.50

28.52

.96415

31.05

25.55

.96197

32.80

27.06

.95970

34.55

28.56

.96409

31.10

25.60

.96191

32.85

27.10

.95963

34.60

28.61

.96403

31.15

25.64

.96185

32.90

27.14

.95957

34.65

28.65

.96396

31.20

25.68

.96178

32.95

27.19

.95950

34.70

28.70

.96390

31.25

25.73

.96172

33.00

27.23

.95943

34.75

28.74

.96384

31.30

25.77

.96166

33.05

27.27

.95937

34.80

28.78

.96378

31.35

25.81

.96159

33.10

27.32

.9.5930

34.85

28.83

.96372

81.40

25.85

.96153

33.15

27.36

.9.5923

84.90

28.87

.96366

31.45

25.90

.96146

33.20

27.40

.95917

84.95

28.92

.96360

31.50

25.94

.96140

33.25

27.45

.95910

35.00

28.96

.96353

31.55

25.98

.96133

33.30

27.49

.95908

35.05

29.00

.96347

31.60

26.03

.96127

33.35

27.53

.95896

35.10

29.05

.96341

31.65

26.07

.96120

33.40

27.57

.95889

35.15

29.09

.96335

31.70

26.11

.96114

33.45

27.62

.95883

85.20

29.13

.96329

31.75

26.16

.96108

33.50

27.66

.95876

35.25

29.18

.96323

31.80

26.20

.96101

33.65

27.70

.95869

85.30

29.22

.96316

31.85

26.24

.96095

33.60

27.75

.95862

85.35

29.26

.96310

31.90

26.28

.96088

33.65

27.79

.95855

35.40

29.30

.96304

31.95

26.33

.96082

33.70

27.83

.95848

35.45

29.35

.96298

32.00

26.37

.96075

33.75

27.88

.95842

85.50

29.30

.96292

32.05

26.41

.96069

33.80

27.92

.95885

35.55

29.43

.96285

32.10

26.46

.96062

33.85

27.96

.95828

35.60

29.48

.96279

32.15

26.50

.96056

83.90

28.00

.95821

35.65

29.52

.96273

32.20

26.54

.96049

33.95

28.05

.95814

35.70

29.57

.96267

32.25

26.59

.96043

84.00

28.09

.95807

35.75

29.61

.96260

32.30

26.63

.96036

34.05

28.13

.95800

35.80

29.65

.96254

32.35

26.67

.96030

34.10

28.18

.95794

35.85

29.70

.96248

32.40

26.71

.96023

34.15

28.22

.95787

35.90

29.74

.96241

32.45

26.76

.96016

34.20

28.26

.95780

35.95

29.79

PERCENTAGE OF ALCOHOL

PERCENTAGE OF ALCOHOL (CosTiNnED)

Alcohol

Specific
Gkavity
AT JgoF.

Alcohol

Specific
Gravity

ATggoP.

Alcohol

Specific
Gravity

ATgJOF.

Per
cent
by vol-
ume

Per

cent

weight

Per

cent
by vol-
ume

Per
cent

weight

Per

cent
by vol-
ume

Per

cent

weight

0.95773

36.00

29.83

0.95523

37.75

31.36

0.95262

39.50

32.90

.95766

36.05

29.87

.95516

37.80

31.40

.95254

39.55

32.95

.95759

36.10

29.92

.95509

37.85

31.45

.95246

39.60

32.99

.95752

36.15

29.96

.95502

37.90

31.49

.95239

39.65

33.04

.95745

36.20

30.00

.95494

37.95

31.54

.95231

39.70

33.08

.95738

36.25

30.05

.95487

38.00

31.58

.95223

39.75

33.13

.95731

36.30

30.09

.95480

38.05

31.63

.95216

39.80

33.17

.95724

36.35

30.13

.95472

38.10

31.07

.95208

39.85

33.22

.95717

36.40

30.17

.95465

38.15

31.72

.95200

39.90

33.27

.95710

36.45

30.22

.95457

38.20

31.76

.95193

39.95

33.31

.95703

36.50

30.26

.95450

38.25

31.81

.95185

40.00

33.35

.95695

36.55

30.30

.95442

38.30

31.85

.9.5177

40.05

33.39

.95688

36.60

30.35

.95485

38.35

31.90

.95169

40.10

33.44

.95681

36.65

30.39

.95427

38r40

31.94

.95161

40.15

.33.48

.95674

36.70

30.44

.95420

38.45

31.99

.95154

40.20

33.53

.95667

36.75

30.48

.95413

38.50

32.03

.95146

40.25

33.57

.95660

36.80

30.52

.95405

38.55

32.07

.95138

40.30

33.61

.95653

36.85

30.57

.95398

38.60

32.12

.95130

40.35

33.66

.95646

36.90

30.61

.95390

38.65

32.16

.95122

40.40

33.70

.95639

36.95

30.66

.95383

38.70

32.20

.95114

40.45

33.75

.95632

37.00

30.70

.95375

38.75

32.25

.95107

40.50

33.79

.95625

37.05

30.74

.95368

38.80

32.29

.95099

40.55

33.84

.95618

37.10

30.79

.95360

38.85

32.33

.9.5091

40.60

33.88

.95610

37.15

30.83

.95353

38.90

32.37

.95083

40.65

33.93

.95603

37.20

30.88

.95345

38.95

32.42

.95075

40.70

33.97

.95596

37.25

30.92

.95338

39.00

32.46

.95067

40.75

34.02

.95589

37.30

30.96

.95330

39.05

32.50

;95059

40.80

34.06

.95581

37.35

31.01

.95323

39.10

32.55

.95052

40.85

34.11

.95574

37.40

31.05

.95315

39.15

32.59

.95044

40.90

34.15

.95567

37.45

31.10

.95307

39.20

32.64

.95036

40.95

34.20

.95560

37.50

'31.14

.95300

39.25

32.68

.95028

41.00

34.24

.955.52

37.55

31.18

.95292

39.30

32.72

.95020

41.05

34.28

.95545

37.60

31.23

.95284

39.35

32.77

.95012

41.10

34.33

.95.538

37.65

31.27

.95277

39.40

32.81

.95004

41.15

34.37

.95531

37.70

31.32

.95269

39.45

32.86

.94996

41.20

34.42

ELEMENTARY APPLIED CHEMISTEY

PERCENTAGE OF ALCOHOL (CoNTiunED)

Alcohol

Specific
Gravity

ATjgoF.

Alcohol

Specific
Gravity
ATigoF.

Alcohol

Specific
Gbavity

ATgg°F.

Per

cent
by vol-
ume

Per
cent

weight

Per
cent
by vol-
ume

Per
cent

■weight

Per

cent
by vol-
ume

Per
cent

weight

0.94988

41.25

34.46

0.94704

43.00

36.03

0.94407

44.75

37.62

.94980

41.30

34.50

.94696

43.05

36.08

.94398

44.80

37.66

.94972

41.35

34.55

.94687

43.10

36.12

.94390

44.85

37.71

.94964

41.40

34.59

.94679

43.15

36.17

.94381

44.90

37.76

.94956

41.45

34.64

.94670

43.20

36.21

.94373

44.95

37.80

.94948

41.50

34.68

.94662

43.25

36.23

.94364

45.00

37.84

.94940

41.55

34.73

.94654

43.30

36.30

.94355

45.05

37.89

.94932

41.60

34.77

.94645

43.35

36.35

.94346

45.10

37.93

.04924

41.65

34.82

.94637

43.40

36.39

.94338

45.15

37.98

.94916

41.70

34.86

.94628

43.45

36.44

.94329

45.20

38.02

.94908

41.75

34.91

.94620

43.50

36.48

.94320

45.25

38.07

.94900

41.80

34.95

.94612

43.55

36.53

.94311

45.30

38.12

.94892

41.85

35.00

.94603

43.60

36.57

.94302

45.35

38.16

.94884

41.90

35.04

.94595

43.65

36.62

.94294

45.40

38.21

.94876

41.95

35.09

.94586

43.70

36.66

.94285

45.45

38.25

.94868

42.00

35.13

.94578

43.75

36.71

.94270

45.50

38.30

.94860

42.05

35.18

.94570

43.80

36.75

.94267

45.55

38.35

.94852

42.10

35.22

.94561

43.85

36.80

.94258

45.60

38.39

.9484.3

42.15

35.27

.94553

43.90

36.84

.94250

45.65

38.44

.94835

42.20

35.31

.94544

43.95

36.89

.94241

45.70

38.48

.94827

42.25

35.36

.94536

44.00

36.93

.94232

45.75

38.53

.94810

42.30

35.40

.94527

44.05

36.98

.94223

45.80

38.57

.94811

42.35

35.45

.94519

44.10

37.02

.94214

45.85

38.62

.94802

42.40

35.49

.94510

44.15

37.07

.94206

45.90

38.66

.94794

42.45

35.54

.94502

44.20

37.11

.94197

45.95

38.71

.94786

42.50

35.58

.94493

44.25

37.16

.94188

46.00

38.75

.94778

42.55

35.63

.94484

44.30

37.21

.94179

46.05

38.80

.94770

42.60

35.67

.94476

44.35

37.25

.94170

46.10

38.84

.94761

42.65

35.72

.94467

44.40

37.30

.94161

46.15

38.89

.94753

42.70

35.76

.94459

44.45

37.34

.94152

46.20

38.93

.94745

42.75

35.81

.94450

44.50

37.39

.94143

46.25

38.98

.94737

42.80

35.85

.94441

44.55

37.44

.94134

46.30

39.03

.94729

42.85

35.90

.94433

44.60

37.48

.94125

46.35

39.07

.94720

42.90

35.94

.94424

44.65

37.53

.94116

46.40

39.12

.94712

42.95

35.99

.94416

44.70

37.57

.94107

46.45

39.16

PERCENTAGE OF ALCOHOL

PERCENTAGE OE ALCOHOL (Concluded)

Alcohol

Specific
Gravity
AT 18° F.

Alcohol

Specific
Gravity

ATggoF.

Alcohol

Specific
Gravity

ATg8°F.

Per
cent
by vol-
ume

Per
cent

weight

Per
cent
by vol-
ume

Per

cent

weight

Per

cent
by vol-
ume

Per

cent

weight

0.94098

46.50

39.21

0.93870

47.75

40.37

0.93636

49.00

41.52

.94089

46.55

39.26

.93861

47.80

40.41

.93626

49.05

41.57

.94080

46.60

39.30

.93852

47.85

40.46

.93617

49.10

41.61

.94071

46.65

39.35

.93842

47.90

40.51

.93607

49.15

41.66

.94062

46.70

39.39

.93833

47.95

40.55

.93598

49.20

41.71

.940-53

46.75

39.44

.93824

48.00

40.60

.93.588

49.25

41.78

.94044

46.80

39.49^

.93815

48.05

40.65

.93578

49.30

41.80

.94035

46.85

39.53

.93805

48.10

40.69

.93569

49.35

41.85

.94020

46.90

39.58

.93796

48.15

40.74

.93559

49.40

41.90

.94017

46.95

39.62

.93786

48.20

40.78

.93550

49.45

41.94

.94008

47.00

39.67

.93777

48.25

40.83

.93540

49.50

41.99

.93999

47.05

39.72

.93768

48.30

40.88

.93530

49.55

42.04

.93990

47.10

39.76

.93758

48.35

40.92

.93521

49.60

42.08

.93980

47.15

39.81

.93749

48.40

40.97

.93511

49.65

42.13

.93971

47.20

39.85

.93739

48.45

41.01

.93502

49.70

42.18

.93962

47.25

39.90

.93730

48.50

41.06

.93492

49.75

42.23

.93953

47.30

39.95

.93721

48.55

41.11

.93482

49.80

42.27

.93944

47..35

39.99

.93711

48.60

41.15

.93473

49.85

42.32

.93934

47.40

40.04

.93702

48.65

41.20

.93463

49.90

42.37

.93925

47.45

40.08

.93692

48.70

41.24

.93454

49.95

42.41

.93916

47.50

40.13

.93683

48.75

41.29

.93906

47.55

40.18

.93679

48.80

41.34

.93898

47.60

40.22

.93664

48.85

41.38

.93888

47.65

40.27

.93655

48.90

41.43

.93879

47.70

40.32

.93645

48.95

41.47

SECTION XII
DETECTION OF COAL-TAR DYE

The use of coal-tar dyes in food and drink, while very
general, is quite unnecessary, and frequently constitutes
fraudulent adulteration. These dyes can usually he de-
tected by the following methods:

Double-Dyeing Process. Sostegni and Carpentieri. If a
solid or semisolid, dissolve 10 to 20 g. of the sample in
100 cc. of water. If a liquid, use from 50 to 100 cc, depend-
ing upon the intensity of the color. Acidify with 2 to 4 cc.
of 10 per cent HCl. Boil nun's veiling or other white
woolen cloth in very dilute KOH or strong soapsuds and
wash thoroughly. Boil a piece about 10 cm. square in the
dissolved- sample until it has been well colored. This usually
takes from five to ten minutes.

Remove the cloth, wash in cold water, and boil in 2 per
cent HCl. After thorough rinsing dissolve the color in hot
dilute NH^OH (1 to 50). Remove the cloth and throw
it away.

Add a slight excess of HCl to the ammonia solution. Im-
merse in this a second and smaller piece of cloth (2x3 cm.)
and boil.

If the dye is of vegetable origin, the second piece of wool

will be practically uncolored in the ammonia solution; if

it is of coal-tar origin, it will take a decided tone, — red,

pink, yellow, green, etc., — depending upon the color of

the sample tested.

DETECTION OF COAL-TAR DYE 77

Arata's Method. Dissolve 20 to 30 g. of the sample in
100 cc. of water and 10 cc. of a 10 per cent solution of
HKSO^. In this mixture boil a small piece of cloth which
has been previously boiled in dilute NaOH and thoroughly
washed in water. Remove, wash in water, and dry between
filter or blotting papers.

•If the coloring matter is entirely of vegetable origin, the
wool will be uncolored or will take a faint pink or brown,
which is changed to green or yellow by ammonia and not
restored by washing.

In addition, double dye, as indicated in the previous
method. If the wool is still uncolored, the dye is of vege-
table origm.

Nun's veiling is a very suitable cloth for these experi-
ments. In removing the natural wool fat many students
make the mistake of boiling it in too strong caustic. A
1 per cent solution is sufficiently strong.

Cochineal and some vegetable colors dye wool directly,
hence the necessity of double dyeing.

Common substances which furnish excellent material for
coal-tar-dye testing are candy, soft drinks, wine, tablets, jam,
jelly, catsup, colored sugars, dessert powders, gelatin, etc.

Well-mounted pieces of wool dyed with these materials
and placed in the notebook give it a living interest.

Detection of Coal-Tar Dye in Butter. Melt a quantity of
butter the size of a marble in a test tube, being careful not
to scorch it. Add an equal volume of Low's reagent and
shake vigorously. Heat nearly to boiling and set aside.
After the acid has settled it will be wine red in the pres-
ence of azo colors. Pure butter fat gives only a faint bluish
tinge, (iow's test.')

Low's Reagent. HC^HgOg, 4 parts ; HjSO^, 1 part. Mix.

78 ELEMENTARY APPLIED CHEMISTRY

Martin's Test. Shake 5 g. of the butter in a test tube
with 20 CO. of Martin's reagent. Let the mixture stand
until the fat has settled to the bottom of the tube. The
dye, if present, will color the supernatant liquid yellow.

Martin's Reagent. CSj, 4 cc. ; C^HjOH, 30 cc. Mix.

Acid and Alkali Test. Melt about 20 g. of the butter in
an evaporating dish and set on a water bath until the curd
and contained water have entirely separated. Pour off the
clear, supernatant fat and filter it through a dry filter paper
in a hot-water funnel or in an oven at 60° C. If the fat is
not clear, it must be filtered again.

Pour into each of two test tubes 2 g. of this filtered
fat dissolved in ether. Into one of the tubes pour 1 cc. of
HCl and into the other the same volume of 10 per cent
KOH. Shake the tubes well and allow to stand. In the
presence of azo dye the test tube to which the acid has been
added will show a pink to wine-red coloration, while the
alkaline solution in the other tube will show no color. If
annatto or other vegetable color has been used, the potash
solution will be colored yellow (^Bulletin No. lOT).

Coal-Tar Dye in Lemon Extract. Lythgoe's Test. To the
original sample add two or three drops of strong HCl.

No change indicates natural color, turmeric, or naphthol
colors.

Pink indicates tropaeolin or methyl orange.

Partial decoloration indicates Martin's yellow.

Complete decoloration indicates dinitro-cresols.

Evaporate 10 to 20 cc. of the sample to dryness, dissolve
the residue in water, and employ the test of Sostegni and
Carpentieri.

Why are flavoring extracts often artificially colored ?

SECTION XIII
IDENTIFICATION OF VEGETABLE COLOES

Caramel. Amthor's Test. Place 10 cc. of the suspected
solution in a Nessler tube or narrow clear-glass bottle. Add
from 30 to 50 cc. of paraldehyde, the latter volume if the
color is very dark. To make the solutions mix, introduce a
few cubic centimeters of absolute alcohol.

If caramel is present, a yellow to dark-brown precipitate
will fall to the bottom of the tube.

Fuller' srEarth Method. Shake 50 cc. of the solution with
25 g. of fuller's earth. Allow the mixture to stand in a
corked bottle of about 2 in. diameter for an hour at room
temperature.

The caramel will be absorbed by the earth, and the super-
natant liquid will appear more or less clear, depending upon
the amount of the absorption.

As some fuller's earth absorbs color more readily than
others, it is advisable to experiment with different samples
upon solutions known to contain caramel.

Amyl-Alcohol Method. Shake 5 cc. of the solution with
10 cc. of amyl alcohol in a small vial for a minute or so.
Allow the liquids to separate.

If caramel is present, the upper layer will be decolorized
to a greater or less extent. The lower layer will be colored
in proportion to the amount of caramel in the solution.

Test vanilla extract, whisky, ginger ale, soft drinks, and

the like for caramel.

ele:mextaey appeied chemistry

Cochineal. Girard and Ihipre's Metliod. If the sample is
catsup, canned fruit, or of this nature, triturate in a mortar
with water until it is reduced to a
very thin paste. Filter, acidulate
with HCl, and shake with amvl
alcohol. If cochineal is present, the
alcohol will be colored yellow or
orange. Separate the amyl alcohol
and wash it with water until neutral.
Add, drop Ijy drop, a very dilute
solution of uranium acetate. In the
presence of cocliineal a beautiful
emerald-green color is produced.

Turmeric. Extract the color with
alcohol. Saturate a filter paper \\ith
the extract and dry at 10iJ° ('. Dip
•ial whisky treated with the paper in a dilute solution of
ainyl alcohol boric acid to which a few drops

Caiainel shows in the hot- ^f ;^() pgj. ^^y^^ \\Q\ ]mye been
toiiniltlie right-hand bottle. , , , t^ r,,

Tiie supernatant liquid is added. Dry the paper, lurmeric
deeoiorized j^. injieated by a distinct cherry-red

coloration. Add a drop of alkali and olive-green will de-
velop (Bulletin M. 51, Unifed Sfati'S Bxreau of (Jliemhlnj,
p. lol).

Fio. 17. True and artifi-
cii

SECTION XIV
EAFFIA DYEING-

Raffia is the cuticle of the leafstalks of the Madagascar
palm QRaffia ruffia). Its tissue is cellulose for the most
part, so the method of dyeing must necessarily differ from
the method followed in dyeing wool, silk, or other animal
fabrics.

A mordant is a substance to "set" a color; that is, to
make the pigment unite chemically, or in some cases physi-
cally, or both, with the material dyed. The principal mor-
dants used in raffia dyeing are alum and other aluminium
salts, and certain salts of iron, tin, and copper.

Raffia is soaked in the mordant solution until thoroughly
impregnated, and then boiled in a solution of the dye, which
forms with the mordant a metallic colored substance known
as a " lake." A lake is relatively insoluble and cannot be
easily washed out.

General Principles. Alum should be used as a mordant
unless otherwise specified. Dissolve 1/4 lb. in 10 qt. of
water. Let the raffia stand in this solution until it has
become thoroughly saturated. From six to twenty-four
hours is generally sufficient. Always untie the bundles
and do them up loosely.

Raffia should not be dry when placed.in the dye. Either

take it directly from the mordant or wet it thoroughly

with water. Let the dye be boiling when the raffia is

placed in it.

82 ELEMENTARY APPLIED CHEMISTRY

Alum spots, grayish patches on the finished product, are
not generally disadvantageous. Most autumn foliage has
a white fungus which, in general appearance, these spots
resemble. A dip in warm water will remove them. Colors
obtained as herein directed will compare favorably with the
bright, soft colors of autumn or the fresh tints of spring.

Do not dye too dark. Lighter tints are more pleasing in
woven and braided work. Dye slightly darker than desired,
as the raffia is lighter when dried. Test pieces may be
quickly dried by holding them against the side of the hot
dye pan. This saves time and affords a convenient means
of judging color value.

Strong dye and short boiling makes soft, flexible, tough
raffia. Weak dye and long boiling makes harsh, brittle
raffia. Some of the coal-tar dyes leave the material glossy,
harsh, and brittle. Fifteen minutes should be the maximum
time of boiling.

Vegetable dyes, in general, give soft, pleasmg tones.
Coal-tar dyes give bright, glossy colors.

Rinse before putting into a dye of another color. DuU,
passive colors may be brightened by boiling in fresh or
stronger dye. Weak dye is of little value. Keep the rafiBa
well covered with dye, and turn frequently.

Dyes extracted from bark, leaves, fruit, roots, vegetables,
wood, and the like should be carefully strained before using.

Save the waste dye, as many beautiful effects may be pro-
duced from it. It is not only economical to use this dye,
but interesting to discover the different colors that may be
obtained.

Time directions are only approximate, as much depends
upon the quality and strength of the dye and on the kind
and amount of mordant absorbed.

EAFFIA DYEING 83

The outer side of the raffia will take a brighter tone than
the inner side. This is especially noticeable in green and
orange tones.

Do not place the full amount of raffia in the pan at
once. Dye a small piece and see if the color suits you. Do
not throw away the material which is displeasing in color,
as it may easily be dyed black or brown.

Experiment by mixing small quantities of various dyes
and mordants in cups and test tubes. You will doubtless
discover some new and pleasing combination.

Material will absorb only a certain amount of the dye.
This amount absorbed, the pigment point is reached. Do
not expect to pour a quart of water at once into a pint cup.

Dye pans should be large enough for the work at hand.
The four-quart or eight-quart size is convenient. The best
results are obtained by using enamel ware.

Preparation of Dyes and Mordants. Dyes and mordants
should be prepared in the following manner :

Butternut. Fill a four-quart pan half full of the husks ;
green ones give the softest tones ; the shells are not objec-
tionable. Cover with water and boil for fifteen minutes.

Cardinal Red. Dissolve a mass the size of a cranberry in
a gallon of water.

Copper Sulfate. Two ounces to a quart of water.

Elderberries. Berries, 1 part ; water, 3 parts.

Fustic Chips. A teacupful to 4 qt. of water. Boil ten
minutes.

Fustic Extract. Dissolve a piece the size of a walnut in a
gallon of water.

Iron Sulfate. Two ounces to a quart of water. Always
use this solution in an old dish, as it will soon ruin a
new one.

84 ELEMENTARY APPLIED CHEMISTEY

Indigo. Use indigo paste (sulfate of indigo). Dissolve a
mass the size of two shoe buttons in 4 qt. of water.

Logwood Chips. See Fustic Chips.

Logwood Extract. See Fustic Extract.

Leaves. Fill a four-quart pan full of the shredded leaves
well pressed down. Cover with water, and boil. Replenish
the water from time to time until the dye appears highly
colored. The usual time is about fifteen minutes.

Onion Skins. The outer skins from half a dozen medium-
sized onions will furnish yellow dye for half a pound of
raffia. Boil until the color is extracted. The time requu-ed
is about ten minutes.

Potassium Ferri-cyanide (Red Prussiate of Potash). Two
ounces to a quart of water.

Potassium Bichromate. Dissolve 1 oz. in a quart of water.
This solution used with red dulls it and gives an orange
tone.

Sumac. Three quarts of the broken cones. Keep well
covered with water and boil for twenty minutes.

Walnut. See Butternut.

Specific Directions for obtaining the Following Colors :

Black. 1. Dye heavily with logwood and place imme-
diately, without rinsing, into a strong, hot FeSO^ solution.

2. Dye as above, substituting oak leaves for the logwood.

Blue. Dye unmordanted raffia m indigo solution to which
two or three drops of H^SO^ have been added. Dry in
direct sunlight. The brighter the light, the bluer the color.
Many tones can be produced by dyeing for different lengths
of time in this solution.

Blue-Green. 1. Boil mordanted raffia in plain indigo solu-
tion and dry away from the sunlight. Raffia dyed with indigo
must be thoroughly rinsed to remove all traces of acid.

RAFFIA DYEING 85

2. Dye in potassium ferri-cyanide to which a few drops
of H^SO^ have been added and mixed thoroughly.

S. Dye as in 2, and place directly into hot iron sulfate.

Brown. 1. Boil in dye from maple leaves until thoroughly
colored. Remove, rinse, and wring out the superfluous
liquid. Then boil in a dye prepared as follows: Strong
butternut dye to which has been added 1/2 pt. of K Cr O
solution and an equal amount of cardinal-red solution.

2. First dye in redwood solution and immerse for about
three minutes in hot, strong logwood.

Light Brown. 1. Boil in clear butternut dye.

2. Boil in clear maple dye.

3. Dye green with fustic and indigo, q.v., and then boil
in a solution of CuSO,.

GJiocolate-Broivn. Dye in sumac and treat with FeSO .

Dark-Brown. Boil in butternut and then in K^Cr^O .

Q-ray-Brown. Equal amounts of sumac, maple, and oak
leaves make a green-brown dye. Since red is the comple-
ment of green, and combined with it makes gray, add
sufficient logwood to brmg to the desired shade.

Olive-Brown. Boil for six minutes in dye from walnut
husks.

Red-Brown. 1. Add a teaspoOnful of alum to walnut
dye and boil in the resulting solution for ten minutes.

2. Dye with cardinal and then with logwood.

3. (a) Dye in redwood solution.

(i) Then dye in a solution made from fustic chips, 3 parts,
and logwood chips, 1 part.

Yellow-Brotvn. Boil first in a dye from maple leaves and
then in Kfirfi^.

Green. Bright Cfreen. Dye yellow with fustic and onion
skins. Place immediately in a strong, hot solution of

86 ELEMENTAEY APPLIED CHEMISTRY

indigo. Dull with iron sulfate to the desired shade. Nearly
all tones can be produced by this method.

Bull Green. Dye with black birch leaves.

Barh Green. Dye with the birch and dip into FeSO .

Gray- Green. Add sufficient ammonia to elderberry juice
to turn it a pronounced green. Boil the raffia in this solu-
tion until the desired shade is produced. The time required
is about eight minutes.

Olive-Green. See Dark Green. Boil longer in the iron
sulfate solution. If left too long, the raffia acquires a heavy
olive tone not pleasing to the eye.

Yellow- Green. Color with fustic or onion skins and very
slightly with indigo.

Gray. For these effects in general, boil in dye from
sumac cones with the stems. A dip in iron sulfate will
produce a pleasant neutral effect.

Old Rose. Dye with sumac berries, discarding all stems.
Substitute elderberries for the sumac.

Orange. 1. Dye in fustic and then in strong, hot redwood
infusion.

2. Boil in butternut for about six minutes. Rinse and
dip into cardinal solution.

To produce a peculiar but pleasing effect, dye first in
fustic and then in cardinal. One side will be brown yellow,
the other a dark red.

Red. With infusions of redwood it is possible to get an
almost complete color scale, from a deep, rich, dark red to
a pale orange. These colors can be dulled with FeSO^,
thus producing an infinite variety of tints and shades.

For a deep red a very strong solution is needed, and only
a small quantity of material can be colored at a time. As
the strength is reduced the color tends toward orange.

EAFFIA DYEING 87

The lighter tints of orange can be dulled with iron sul-
fate to give a pleasing light brown, practically identical
with that produced from sumac.

Bright Red. Dye in sumac and strengthen in cardinal,
or dye directly in the cardinal.

Bark Red. 1. Dye a bright red and dip in iron sulfate.
The longer it remains the darker it becomes, until the limit
is reached.

2. Dye brown with waste dye and then boil in cardinal.

Indian Red. 1. Dye orange red and boil in CuSO for
two minutes.

2. Dye light brown and boil first in cardinal solution
and then in potassium dichromate.

3. To butternut dye add half as much cardinal solution,
one eighth as much KgCr^O,, one fourth teaspoonful of
indigo paste, 2 oz. of logwood chips. Boil and strain, and
dye the raffia in the clear liquid.

4. To produce a pale shade, dye in an extra strong solu-
tion from the sumac berries after discarding the stems.

Purple-Red. Dye in cardinal and then in indigo, or dye
alum-mordanted raffia in logwood.

Yellow. Any of the yellow tones may be intensified by
longer boiling.

Lemon Yellow. 1. Boil in dye from pear leaves to which a
spoonful of alum has been added. Alum intensifies the color.

2. Boil for one minute in fustic, or for the same length
of time in onion skins.

Any of the colors herein described can be duplicated,
provided the experimenter becomes familiar with the special
dye at hand.

Raffia dyemg is not merely a mechanical process ; it is
an art learned best by the patient and orderly worker.

SECTION XV
CHEMISTRY OF STAINS

A stain may be caused by the union, chemical or physi-
cal, or both, of some substance with a suitable medium, as
paper, cloth, skin, and the like. The subject is a very deep
and intricate one.

When a stain is purely physical, as, for example, a spot
of grease on cloth, physical means of removing it are best ;
that is, some simple process of absorption or solution.

When the stain is of a chemical nature and certain oxids
are formed, — take, for example, the stain of apple juice on
cloth, — chemical means must be employed to reduce or
" bleach " the oxid.

When a stain is of both a chemical and physical nature,
both physical and chemical means should be employed to
remove it. A stain of this character may be illustrated by
an mk spot on cloth.

A good general bleaching reagent consists of a double
solution kept in separate bottles.

No. 1. Acetic or tartaric acid solution, 20 per' cent.
No. 2. Five grains of bleaching powder (CaClOj). Boil in 100 cc.
of water until a pink color appears. Filter and add 50 cc. of cold water.

This combination is sometimes called " ink eradicator." It
must not be applied to silk or to fabrics of deUcate color.

To remove stains of ink, coffee, tea, fruit, and dye, wet
the spot thoroughly with No. 1. Absorb the superfluous
liquid with a blotter and apply No. 2. Rinse and repeat,

CHEMISTRY OF STAINS

if necessary. If a persistent, yellowish spot remains, as is
often the- case when woolen goods have been treated,
remove all traces of the reagents and saturate with fresh
H^O^. Common stains may be removed by treating as
shown in the following table:

Stain

Removjed by

Acids

Cold water, Nos. 1 and 2

Grass and fruit . . .

Cold water, alcohol, Nos. 1 and 2

Grease

Gasoline, carbon tetrachlorid, chloroform,

ether, carbon bisulfid, ammonia, soapsuds.

warm fuller's earth (cover with a blotter

and apply a warm flatiron)

Dyes, coal-tar or of vege-

table origin . . .

Nos. 1 and 2, ammonia

Mildew . ....

Nos. 1 and 2, sunlight

Inks

Nos. 1 and 2

Inks, indelible (silver) .

Potassium cyanide, 10 per cent. Use great

caution, intensely poisonous. Sodium hypo-

sulflte, 20 per cent

lodin

Methyl alcohol, potassium iodid solution,

10 per cent

Iron rust

"Warm oxalic or citric acid, 10 per cent. If in

silk, let it alone

Paint, varnish ....

Turpentine, benzine, carbon tetrachlorid. Use

no turpentine on silk

Tar, wagon grease . .

Soap and oil, turpentine

SECTION XYI

FOOD PRESERVATIVES

Detection of Sulfurous Acid. Weigh about 25 g. of the
sample into a 200-cc. Erlenmeyer flask. Add water, if nec-
essary, to form a thin paste
and about 5 g. of sulfur-free
zinc. Introduce 10-20 cc.
chemically pure HCl. Over
the mouth of the flask place
a small filter paper which
has been wet with a strong
solution of Pb (N0,)„. Heat
gently. The blackening of
the filter paper indicates the
presence of sulfites. Why ?
A mere browning of the filter
paper sliould not be accepted
as evidence of the inten-
tional addition of SO^, either
as a preservative or as a
bleaching agent ; it must be
distinctly black. (^Bulletin
No. 107, ]). 187:)

Distillation Method. Leach.
Reduce 100-200 g. of the
sample to paste as before,
and acidif}' with .5 cc. of

Fig. 18. Apparatus arranged for

the detection of sulfurou.s acid by

tile distillation method

FOOD PKESEEVATIVES 91

20 per cent phosphoric acid. Transfer to a boiling flask and
distil. Arrange the apparatus so that the outlet of the con-
denser will dip below the surface of a little water, about 20 cc.

Distil off 20 to 30 cc. Treat the distillate with 5 to 10 cc.
of bromin water and boil for a minute or so.

Without waiting for the distillate to cool, add a little
BaClj. A white precipitate indicates sulfurous acid.

What is this precipitate ? Test its solubility. Of what
use is the bromin water ?

Test molasses, lime juice, mushrooms, Hamburg steak,
sausage, etc. for sulfurous acid.

Determination of Sulfurous Acid by Direct Titration. Care
must be taken in applying this method to other products
than wine to determine whether the iodin is decolorized by
any substance that may naturally be present.

Macerate 25 g. of the sample, if a solid or semisolid, with
sulificient water to form a thin paste. Place in a 200-cc. Erlen-
meyer flask. Add 25 cc. of normal KOH, mix thoroughly,
and allow it to stand for fifteen minutes, shaking from time
to time. Add 10 cc. of dilute sulfuric acid (1 to 3) and 5 cc.
of freshly prepared starch solution. Rapidly titrate the mix-
ture with N/50 iodin solution until a blue color is perma-
nent for several minutes.

One cubic centimeter of N/50 iodin solution is equivalent
to 0.00064 gram of sulfur dioxid.

From the per cent of SO^ calculate the per cent of sulfur-
ous acid in the original sample (^Bulletin No. 107, p. 188).

Detection of Boron Compounds — Borax or Boric Acids. It
is not uncommon to find this forbidden preservative in
cheese, ice-cream cones, fancy crackers and biscuits. It was
formerly used in canned meats, but the practice has greatly
declined of late.

92 ELEMENTARY APPLIED CHEMISTRY

" The common symptoms observed after long-continued
doses of borax or boric acid in food are headaches, sensations
of fulhiess in the head, uneasiness and nausea in the stomach,
and disturbances of the digestion and appetite" (^Wiley).

Discover the Effects of H3BO3 upon Turmeric Paper and
Turmeric Tincture. Break about 10 g. of saltines or other
crackers into a crucible. Add a pinch of boric acid or borax,
and ash. Acidulate the ash with a drop or so of HCl and
dissolve in as little water as possible.

(a) Dip a strip of turmeric paper in the solution and
allow it to dry. Result ?

(5) Mix the remainder of the ash solution with a cubic
centimeter of turmeric tincture in a watch glass and evapo-
rate over a water bath. Result ?

Confirm both (a) and (6) by placing a drop of dilute
alkali upon the paper or on the contents of the glass. An
olive-green color should appear.

After becoming familiar with the reaction between boric
acid and turmeric, test crackers or biscuits, butter, cheese,
canned meat, and shrimps for boron compounds.

Method. Ash about 10 g. of the sample, first adding
enough limewater to make an alkaline reaction. Acidulate
the ash with a drop or two of HCl. Dissolve in a few
drops of water. Test with the turmeric paper and with the
turmeric tincture, as outlined.

If the turmeric is reddened by the solution of the ash
and turned olive-green by dilute alkali, boric acid, free or
combined, is present in the sample.

Boron Compounds in Butter. Melt 25 g. of the sample
on a water bath and allow the aqueous solution to settle.
Decant this solution and acidulate with a drop or so of dilute
HCl. From this point apply the regular turmeric test.

FOOD PRESERVATIVES

Detection of Salicylic Acid (HC,H503). This compoiuul
has lieen used i'dr thu preservation of catsup, jams and
other fruit products, and beer. Ileduce tlie sample to a
tliin paste with water, if it is not
already a licpiid. Acidify sliglitly
with dilute II SO,. Shake with an
equal volume of chloroform in a
closed flask or separatory funnel.
Separate the chloroform and allow
it to evaporate spontaneously.

Firtit Tvat. To a part of the
dry lesidue add a drop of ferric
chlorid and an ecpial volume of
water. A pronoruiced violet or
jiurple color indicates the pres-
ence of salicylic acid.

Scriind Ti:i<t. Heat the remainder
of the residue gently with a few
drops of 2(.) per cent II,S(J^ and
a cubic centimeter of methyl
alcohol.

If salicylic acid is present,
a pronounced odor of "winter-
green," or methyl salicylate, will
be apparent.

Detection of Benzoic Acid
(HC^HjOJ. Benzoic acid is used
for much the same purpose as
salicylic acid, and is more often found in food products.

Extract tlie sample as for salicylic acid and evaporate
the chloroform. Dissolve a i)art of the dried residue in
ammonia and evaporate to drj-ness o\'er a water Ijath.

Fig. 19. Sep;iratiiry funnel

t'(ir extr;icting salicyliu or

benzoic acid with etlier or

clilorofin'Tu

Siililimcil crystals of benzoic

at-id slH.tA\' un tile A\'atc]i glass.

See Fig-. liO

ELE^IEXTAEY APPLIED CHE.^IISTRY

Firf't Test. Dissolve in a few drops of water, heating
genth- to effect the sohitioii. Filter into a small test tube
and add a drop of ferric chlorid. A flesh-colored precipi-
tate of ferric lienzoate assures the presence of benzoic acid.

Second Test. Dissolve the
remainder of the chloroform
extract in ammonia and evap-
orate to dryness in a tA'\-o-incli
watch glass. In^•ert a second
watch glass over the first.
Jjctween these insert a fil-
ter paper from the center of
which has been cut a lialf-
inch circle. Clamp the watch
glasses closely together and
lieat at a \n\y temperature
on a sand bath. If l)enzoic
acid is present, needlelike
crystals Avill sublime on the
upper watch glass. Examine
them witli a low-power lens.
Dissohe and treat them with
a drop of ferric chlorid, as
in the preceding test.
Detection of Saccharin. Prepare the sample as for the
salicylic acid test. Extract with ether and allow the latter
to evaporate at room temperature. A distinctly sweet taste
mdicates the presence of saccharin.

Add a small piece of NaOH and heat gently. The sac-
charin \\\\\ be converted into salicylic acid and can be
detected by the ferric chlorid test.

Fk:. 20. Saiul bath, lilter iiaper,

and double watch glass arranged tu

sublime benzoic acid

SECTION XVII

EXAMINATION OF TOOTH POWDERS

The usual ingredients of these dentifrices are soap pow-
der, precipitated challi (CaCOg), sugar, orris root, and other
flavoring materials.

Sometimes powdered pumice stone and cuttlefish bone are
substituted for the chalk. Since these substitutes scratch
the enamel, they are injurious and should be avoided. They
may be detected as follows :

Shake up 1 to 2 g. of the powder with 10 cc. of dilute
alcohol. To the residue add about 4 cc. of HCl and an
equal volume of water. Note any effervescence. Boil.
Allow any undissolved matter to settle and decant the
solution. Insoluble matter indicates pumice stone. Con-
firm by placing a little on a glass plate and rubbing gently
with a glass rod. If pumice is present, a scratching sound
will be heard.

Divide the decanted solution into two parts.

The First Part. Evaporate to dryness and test with
ammonium molybdate for the PO^ radical. If present,
cuttlefish bone is indicated.

The Second Part. Test for calcium with (SYi^pp^.
Its presence is indicated by a flocculent white precipitate.
This further bears out the suggestion of the presence of
powdered bone.

96 ELEMENTARY APPLIED. CHEMISTRY

TABLE OF INDICATIONS

Effe rvescence

Residue Insol-
uble IN Ha

Calcium

PO4

Indication

Yes

Chalk

Yes

Cuttlefish bone

Yes

Pumice

Yes

Chalk and pumice

Yes

Cuttlefish bone
and pumice

What are the indications for chalk and cuttlefish bone ?
In addition to the above tests, determine the free and
combined allcali and the alkaline carbonates.

SECTION XVIII

EXPEKIMENTS WITH GLUCOSE

Glucose is widely distributed in the vegetable kingdom.
It occurs naturally in many fruits and vegetables, in honey,
in the blood, liver, and urine. In the disease diabetes mel-
litus the quantity present in the urine is sometimes as high
as 10 per cent.

It is artificially prepared on a large scale by treating
corn or potato starch with dilute sulfuric acid. Its sweet-
ness to that of sugar is as 3 to 5. Large quantities are
annually consumed in the manufacture of leather, candy,
table sirups, jams, jellies, and the like.

Conversion of Starch into Glucose. Boil 5 to 10 g. of
sawdust, filter paper, cotton rags, or cornstarch, with a
10 per cent solution of H^SO^ in an Erlenmeyer flask, in
the neck of which is a funnel to act as a reflux condenser.
Continue boiling until the liquid becomes a decided yellow
or brown. Neutralize with powdered chalk and filter.
Evaporate the filtrate to a thick sirup.

Suggestions. Pour the acid into the water.

Flasks will break if the starch is allowed to stick to
the bottom. For the first attempt use corn or potato
starch.

Replenish the water as it boils away. If the acid becomes
too strong, it will carbonize the starch.

Neutralize by adding the chalk well powdered. Test
often with litmus. Filter. If the filtrate is still acid, add

98 ELEMENTAEY APPLIED CHEMISTRY

more of the carbonate. A relatively large quantity will
probably be required.

Add plenty of water to the filter to wash the glucose
from the spent carbonate.

Great care must be taken during the process of evapora-
tion or the liquid will blacken. Stir constantly and finish
over a water bath.

Reactions. Notice the interesting exhibition of catalysis in
the following reaction :

starch • glucose

C^H^P^ and H^S0, + CaC03 = ?

Name the contents of the filter paper. Dry it. It will
keep its form. Why ? Which of the changes in the above
experiment are physical, and which are chemical ?

Test for Glucose by the Reduction of a Copper Salt. Dis-
solve a little glucose in water. Add 2 cc. Fehling's solu-
tion, 1 cc. each of No. 1 and No. 2. Heat nearly to boiling.
The result is characteristic.

Repeat, substituting cane sugar for the glucose. Result ?

Fehling's Solution, No. 1 : CuSO^, 34.6 g. ; water, 500 ec.
Fehling's Solution, No. 2 : Rochelle salts, 173 g. ; NaOH, 50 g. ;
water, 500 cc. Keep in separate bottles.

Test for Glucose by the Precipitation of Dextrine. Dis-
solve a little glucose in water. To two or three cubic centi-
meters add a large excess of methyl alcohol. Agitate. The
glucose is precipitated as dextrine.

Repeat, substituting cane sugar for glucose. Result ?

Inversion of Cane Sugar. Make a solution of cane sugar
as before. Add one drop of HCl and boil vigorously. Test
with Fehling's solution.

C..H,p„ + H,0 = C,H,,0, + Q^l\p,

cane eugar glucose fructose

EXPERIMENTS WITH GLUCOSE 99

The mixture of glucose and fructose is called invert
sugar. Notice how the inversion is brought about by hydrol-
ysis. Before cane sugar is digested it must pass through
the process of inversion.

Test honey, confectionery, maple sirup, molasses, jam,
jelly, the contents of pies and cake fillers for invert sugar
by the Fehling method.

Test the same for glucose by the precipitation of dextrine.
It is instructive to treat a sample of homemade jelly and
any one of the cheap varieties by this method. A decided
milkiness in the alcohol indicates commercial glucose.

Many soft candies, waxes, taffies, a large proportion of
stick candy, caramels, and the like are made with glu-
cose. Sometimes a little cane sugar is added to give it a
sweeter taste.

Considerable glucose is used in the manufacture of table
sirups. These are sent to the market under euphonious
names, as "Maple Drip," "Bon Ton," "Golden Drip,"
" White-Loaf Drip," etc.

Detection of Glucose in Honey. Dissolve one part of honey
in an equal volume of water. Cool and add 5 to 8 drops of
a dilute solution of iodin in KI.

If the honey solution remains a pale yellow, commer-
cial glucose is probably absent. If decolorized, glucose is
indicated.

If starch is present, the characteristic blue-to-purple
coloration will appear (Beckmmis tesf).

Anilin-Acetate Test for Artificial Invert Sugar in Honey.
The reagent must be freshly prepared. Shake 5 cc. of
chemically pure anilin with 5 cc. of water, and add 2 cc. of
glacial acetic acid. The milky emulsion of anilin and water
should clear up perfectly upon the addition of the acid.

100 ELEMENTARY APPLIED CHEMISTEY

Dissolve about 5 cc. of honey in a test tube with an equal
volume of water, and pour a little of the anilin solution
down the sides of the tube so as to form a thin layer upon the
surface of the liquid. If artificial invert sugar is present, a
red ring will form beneath this layer, and on gently agitat-
ing the tube all of the acetate will be tinged this color.

If the honey is pure and has not been overheated, no
trace of the red will be found.

Sugar in Vegetables and Fruits. Grind a quarter of a
turnip or half an apple through a food cutter. Place the
pulp in a piece of cheesecloth and squeeze the juice into a
beaker. Taste the juice. Pour about 5 ce. into a test tube
and dilute with three or four times its volume of water.
Test with Fehling's solution.

Test beets, carrots, parsnips, etc., for sugar. How does
the sugar from the beet differ from that of the apple ?

Conversion of Starch to Invert Sugar by the Process of
Mastication. Grind a few grams of soda or milk crackers in
a mortar with enough water to form a thin paste. Transfer
to a test tube and test with Fehling's solution. Result?

Thoroughly chew about 5 g. of the cracker for about
one minute. Test as before. How do you account for the
change ? Could the food be chewed too much ? Why ?

Detection of Adulteration in Maple Sirup. Coloring Matter.
Shake 15 cc. of the sirup with 3 cc. of amyl alcohol and
1 cc. of Hj^PO^ (20 per cent). Allow to settle. The amyl-
alcohol layer should be a decided brown. Adulterated
samples give a straw-to-light-brown color.

Foam Test. Mix 5 cc. of the sirup and 10 cc. of water in
a graduated tube and shake vigorously for half a minute.
Allow to stand ten minutes. The foam should not measure
less than 3 cc. Adulterated samples give less foam.

EXPERIMENTS WITH GLUCOSE 101

Precipitate Test. Mix 5 ec. of the sirup with 30 cc. of
water in a 50-cc. cylinder. Add 2 cc. of lead subacetate
solution. Mix well and allow to stand for twenty hours.
The precipitate should not measure less than 3 cc. (^Bulletin
of Pharmacy, December, 1908.')

When maple sugar is to be tested, dissolve 15 g. in
enough water to make 15 cc. of sirup.

SECTION XIX
EXAMINATION OF HEADACHE POWDEES

A great deal of injury is done each year by the in-
discriminate use of headache powders, " cures," " stops,"
tablets for car sickness, anti-pam tablets and pills, cold
" cures," and the like.

Many of these contain a coal-tar derivative commonly
known as acetanilid, or antifebrin. This is the acetyl de-
rivative of anilin, and is therefore called phenylacetamid
by the chemist. This substance is a dangerous heart de-
pressant and should never be used except by the intelligent
advice of a physician.

Another substance frequently used in cheap powders of
the above description is phenacetin, known to the chemist
as oxyethylacetanilid. If one values his health, he should
avoid the common use of such pernicious drugs.

Detection of Acetanilid in Headache Cures, Cold and Grippe
Powders, and like Nostrums. Strobel's Test. Place about
0.2 g. of the sample in a 5-in. test tube and add about
the same volume of ZnCl^. Heat gently, meanwhile hold-
ing a wood shaving or splint down the mouth of the tube.
White fumes soon appear. Continue heating ; the mixture
melts, turns light yellow and finally black. Observe the
shaving from time to time. If it is stained yellow, acet-
anilid is undoubtedly present. Note the peculiar odor of
the fumes. Varnish or shellac the splint and mount it in
the notebook with the label from the package.

102

EXAMINATION OF HEADACHE POWDEES 103

Ritsert's Test, lioil 1 g. of the sample in a small l)eaker
for two or three minutes \\'ith alx.iut 3 ce. strong HC'l. Cool
and di^'ide into three portions and test in small tul)es.

1. Add carefully 1 to 3 drops of a solution of bleaching
powder (CaClOJ, 1 to 200, in sueh a manner that the two
liquids do not mix. A beautiful blue eoloi' is seen at the
junction of the two li(puds
if acetanilid is present.

This is known as the in-
dophenol reaeti(in, and it le-
sponds to anilin compounds
generally.

2. To another purtion add
a small drop of KAIn() . ^V
clear green color is formed
if an appreciable amount of
acetanilid is present.

3. ]Mix the third portion
with a 3 per cent chi'c imic acid
solution. Acetanilid gives a
green color, changing to a
dai'k green in a few minutes,
and forms a dark blue precipitate on the addition of a drop
or two of NaOH solution.

In the case of powders containing A'egetaljle matter or
sugar of milk, both of which will turn brown on heating with
HC'l, it is advisable to first boil the sample in 5 t(_i 10 cc. of
water. Filter, cool the liltrate, and agitate. If acetanilid is
present, it will crystallize out and settle. ^V centrifuge may
be used t(.) advantage to separate the crystals from the licjirid.
This latter which still contains some acetanilid in solution
may be discarded and the crystals tested as indicated.

Fh.,. 21. Showing iiu'tliod of Iiold-
iiig .splint for tlio Strobel test

104 ELEMENTARY APPLIED CHEMISTRY

The blue color of the bleaching powder solution is prob-
ably due to the presence of anilin hydrochlorid.

Test headache powders for the bromin radical by gently
heating with equal parts of MnO^ and H^SO^.

Isonitril Reaction. Heat about a gram of the powder with
10 cc. of a 10 per cent NaOH solution. Remove from the
flame and cautiously add a few drops of chloroform. Set
aside for a few minutes. If acetanilid is present, the greasy,
disgusting odor of phenylcarbamine will be apparent.

This last test is perhaps the best of all, and is especially
applicable to a liquid or solid whose color might interfere
with the Ritsert test.

To determine the Per Cent of Acetanilid present. Dis-
solve a definite weight of the powder, about 1 g., in hot
water. Boil and filter. To the filtrate add bromin water
until the yellow color persists. The acetanilid is precipitated
as p-bromacetanilid. Dissolve the precipitate in benzol.
Filter and evaporate the benzol over a water bath. Dry at a
temperature not exceeding 100° F. Weigh the residue.

Caution. Keep the benzol from all flame, as it is exceed-
ingly inflammable.

Pure acetanilid melts at 113° C. Determine the melting
point of your sample.

If vinfamiliar with any of the above tests, work with a
known sample. Do not give up until you are familiar with
them. You may save the life of some one.

SECTION XX

TESTS FOR ARSENIC

Arsenic is one of the most widely distributed elements.
Unless care is taken by the manufacturer, it may contami-
nate our foods, articles of clothing, wall papers, paint, and
the like. In testing any such substance for arsenic it is
advisable to partially destroy the organic matter with a
mixture of sulfuric and nitric acids. This treatment oxi-
dizes the arsenic into arsenic acid, which may be completely
removed with boiluig water. The method advised is that
of Chittenden and Donaldson (^Bulletin No. 86, Bureau of
Chemistry, United States Department of Agriculture').

To successfully perform tests for arsenic, it is absolutely
necessary that all of the reagents are themselves free from
it. Assure yourself of this first of all. Save time by putting
a few scraps of arsenic-free zinc into four different flasks :

No. 1 containing 10 per cent HCl.

No. 2 containing 10 per cent H^SO^.

No. 3 containing 10 per cent nitro-sulfuric acid.

No. 4 containing 10 per cent HCl and a few drops of
10 per cent CuCl^.

Over the mouth of each flask place a piece of filter
paper, which has been wet with a few drops of concen-
trated solution of mercuric chlorid. There should be a
brisk evolution of gas.

If after half an hour the filter paper shows no discolor-
ation, the reagents are suitable for use.

105

lUIJ

ELE.MEXTAEY APELIED CHE:\riSTET

Preparation of the Sample. Wall Paper, Cloth, etc. Place
al;)ont 25 sq. cm. cif the sample cut into small pieces in an
evaporating dish. Treat with 1 to 5 cc. of a mixtttre of con-
centrated sulfuric and nitric acids, 30 to 1, both of which
have been jjroved free from arsenic. Add a few drops of

Fig. 22. Gutzeit apparatus for the detection of arsenic
Showing wash hottle witli fuitlet capped with preiiareil filter i>aper

water and allow the action to proceed for hve minute.s.
Heat with a low flame until all of the acid is dri\-en off,
or until the residue lias granulated and tlie fumes have
nearly disappeared. Break up tlie charred mass, add a little
water, and boil to get rid of the 11 SO^. Filter througii a
small Alter and -wash to about 40 cc.

TEST.S FOR AESEXKJ

107

Preparation of the Sample. Jlrats, IW/rtahlcs, et<: Meat in
a i:)nrceliiin dish about 100 g. of tlie sample ^A-itli 23 ec. of
HNOg, stii-ring occasionally with a glass roil. When the
substance has become a deep yellow or orange color, remove
from the heat and add 3 cc. of H„SO,. Stu- the contents of
the dish while the nitrous
fumes are gi^'en off. Care
should be taken to pro-
tect the hands from these
fumes.

1 1 eat gently and add
while hot, drop by drop,
8 cc. of UNO , stirring the
mass constantly. Heat
more strongly until acid
fumes come off and a
charred mixture remains.
Break this up, extract
with boiling -water, and
filter as in the case of
wall paper.

Note. Always conduct
these prelimbiary proc-
esses under a gas hood
or out of doors.

The Gutzeit Test. Into a clean Erlenmeyer flask of about
200 cc. capacity, fitted with a thistle tube and a right-
angled delivery tube, place a few pieces of arsenic-free
zinc. Slide the zinc gently uito the flask to avoid breakage.
Pour in the filtrate from the prepared sample and about
5 cc. of the tested HCU, containmg lialf a cubic centimeter
of a 10 per cent solution of CuCl, of known purity.

Fn;.23.

Siuqili' form of Gutzeit
apparatus

rtliowiug till' prepared tilter paper held
over the mouth of the flask

108 ELEMENTARY APPLIED CHEMISTEY

Allow the escaping gas to pass tlirougli a few cubic
centimeters of lead acetate solution contaiQed in a small
wash bottle or potash bulb, and impinge upon ai piece of
Swedish filter paper which has been wet with a drop or so
of a concentrated solution of mercuric chlorid.

If after haK an hour the paper shows a stain yellow
to deep orange, arsenic is present. The color varies with
the amount. Very large quantities produce a yellowish-
brown stain.

Write the reaction between free hydrogen and arsenic.
What compound causes the yellow color on the filter paper ?
If the filter paper remains white, freedom from arsenic is
assured.

Place a little chemically pure 10 per cent HCl upon per-
fectly pure zinc. Result ? Then add a few drops of CuCl^
solution. How do you explam the effect ? Why was the
copper chlorid solution added to the origmal sample ?

iNIake arsenic tests upon the following : wrapping paper,
samples of cloth, candy wrappings, wall paper, etc. Liquids
can usually be tested without subjecting them to the pre-
vious preparation.

SECTION XXI
METHOD FOR TESTING PAINT AND OILS

If one desires to paint his building with a lead and zinc
paint and pays the price, he should get lead and zinc, not
sand, lime, and barium sulfate or barytes. On the other hand,
if he pays a sand-and-lime price, he should not expect to get
a metallic article. Which kind have you seen used ?

Extraction of the Oil. Place about 5 g. of the paint in
a small flask or beaker and wash with successive portions
of warm petroleum ether, or benzine. Heat this in a water
bath, away from any flame. Continue the washing until a
few drops leave no residue on evaporation.

It is more convenient to conduct the extraction with a
Soxhlet apparatus, placiiag the paint in an extraction shell
the weight of which must be previously determined. Dry
the undissolved residue at 100° C. and calculate the per
cent of the oil.

To test the Purity of the Oil. Evaporate the ether extract
from the previous experiment. Warm 2 cc. of the oil so
obtained in a test tube and add an equal volume of glacial
acetic acid. Cool in running water and add one drop of con-
centrated H^SO^. Pure linseed oil turns sea-green, the color
deepening on standing. A fugitive violet color indicates
rosin oil.

Heat a little of the oil in a test tube to about 100° C.
Cool and rub on the back of the hand. If present, fish oil
will be detected by the characteristic fishy odor.

109

110 ELEMENTARY APPLIED CHEMISTRY

To test the Body of the Paint. 1. Boil a portion of the
residue with strong acetic acid. A residue indicates BaSO^
or sand (SiO^), or both. Save the filtrate.

2. To a second portion add an equal volume of Na^COg,
then mix and fuse with a blowpipe on charcoal. If lead is
present, a small metallic globule will fuse out. Lead in
paint is usually present iu the form of basic lead carbonate,
2PbC03-Pb(OHX.

3. Moisten a third portion with a solution of Co (NOg)^.
Heat strongly as before. A green color indicates zinc.
Probably ZnO is in the original paint.

4. To the filtrate from 1 add an excess of NHOH

and then ammonium oxalate. If lime is present, a white
precipitate of oxalate of lime is formed.

Suggest a method for determining how much of each
ingredient is present.

Test for the Purity of Olive Oil. Shake equal volumes
(5 cc.) of the oil and HNOg. Pure oil should turn from
pale to dark green in a few minutes. If it changes to brown,
red, or orange, the addition of a foreign oil is indicated.

Heat for five minutes in a water bath at 100° C. It should
become pale yellow to orange yellow. On standing it will,
if pure, become a yellow solid. (LeacKs test?)

Free Fatty Acids in Olive Oil. Weigh exactly 20 g. of
the sample into a counterpoised Erlenmeyer flask and add
50 cc. of neutral alcohol. Mix thoroughly and heat the
contents to 60° F.

Titrate with tenth-normal sodium hydrate, using phe-
nolphthalein as an indicator. Shake the mixture often dur-
ing the titration. The number of cubic centimeters of the
alltali used to neutralize the acid in 1 g. of the oil is called
the Acid Xumber.

METHOD FOE TESTING PAINT AND OILS 111

Each cubic centimeter of tenth-normal sodium hydrate
equals 0.0282 g. of oleic acid. Tabulate the results as Acid
Number and also as Per Cent of Oleic Acid.

The fresher and better grades of olive oils contain the
least amount of free fatty acid.

Neutral Alcohol. Titrate any convenient volume of 95 per cent alco-
hol with tenth-normal alkali, using phenolphthaleiu as an indicator.

BACH'S TABLE POR OIL REACTIONS

Kind of Oil

After Agitation

■WITH HNO3

After Heating

FOR Five Minutes

ON Water Bath

Consistencv
after standing

Twelve to
Eighteen Hour.s

Olive ....

Pale green

(_)range to yellow

Solid

Peanut

Pale rose

Brownish yellow

Solid

Rape . .

Pale rose

Orange yellow

Solid

Sesame . .

White

Brownish yellow

Liquid

Sunflower . .

Dirty white

Reddish yellow

Buttery

Cottonseed .

Yellowish brown

Reddish brown

Buttery

Castor . .

Pale rose

Golden yellow

Buttery

Detection of Cottonseed Oil in Olive Oil. Take any con-
venient volume of C-S,^ m which 1 per cent of sulfur has
been previously dissolved, and add an equal volume of
amyl alcohol (fusel oil).

To 5 cc. of the sample add an equal volume of the re-
agent. Stop the test tube loosely with cotton and heat for
fifteen minutes in a bath of saturated boiling brine.

If cottonseed oil is present, a deep red to orange color is
developed. Pure olive oil gives little or no color under this
treatment. (HalpJien tesf)

This test can also be used for the detection of cottonseed
oil in lard. The fat from animals fed on cottonseed meal is
said to give a faint reaction.

112 ELEMEJSTTAKY APPLIED CHEMISTEY

If the olive oil containing cottonseed oil has been pre-
viously heated, the reaction is much less delicate.

Kapok oil, from the seeds of the Eriodendron anfraetuo-
sum, and baobab oil give the same reaction. A distinction
can, however, be made, since the two last oils react without
heating, while cottonseed oil must be heated.

To distinguish Renovated from Creamery or Dairy Butter.
Melt two or three grams of butter in an iron spoon. Pure
butter melts quietly with the production of much foam.
Renovated butter and oleomargarine bump and sputter like
hot grease and produce no foam to speak of.

Waterhouse Test for Oleomargarine. Thoroughly shake
50 cc. of sweet milk and heat nearly to boiling. Add from
2 to 5 g. of the sample and stir with a small wooden stick
flattened at one end until the fat is entirely melted.

Place the beaker in a dish of ice water and continue
stirring until the fat solidifies.

If the sample is oleomargarine, the fat can be collected
into a lump. Butter fat cannot be so collected, but is more
or less emulsified with the milk.

If the sample is renovated butter, it will tend to collect
as a film on the surface of the milk when the stu-ring is
stopped. It does not clot or gather like oleomargarine, but
usuall}' adheres to the wooden rod.

SECTION XXII

DETEEMINATION OF FOOD VALUES

Total Nitrogen and Proteids of Cereal Products. Gunning's
Method. This method consists iia decomposing the organic
matter by prolonged digestion with sulfuric acid and potas-
sium sulfate. The carbon is driven off as CO^ and the
hydrogen as water. The nitrogen is converted into am-
monium sulfate from which the free ammonia is liberated
by means of an alkali and distilled into a known volume
of N/10 acid, and the amount calculated by titrating the
acid remaining.

It should be observed that foods in their natural state
seldom if ever contain nitrates. Should this radical be
present in appreciable amounts, the Gunning method must
be modified.

Prove the absence of nitrates by extracting about 5 g.
of the sample with water. Filter and test the filtrate by
mixing with a solution of ferrous sulfate. Add concentrated
sulfuric acid so as to form a layer below the mixed solution.
In the presence of nitrates a dark brown ring forms at the
juncture of the two liquids.

Prove the reliability of this reaction by working with a
solution known to contain a nitrate.

In the absence of nitrates proceed with the Gunning
method as follows :

Weigh exactly 0.5 g. of the finely powdered sample —
bread, macaroni, breakfast food, etc. — and transfer to a

113

114

ELH.MEXTAr.Y APPLIED ('IIE:N[ISTRY

clean, dry Kjcldalil flask of about 250 cc. volume. jVdd
10 g. of K.,SO^ and from 15 to 25 cc. concentrated H.,SO .
Incline the flask at an angle of about 75° over a small bare
flame and licat gently until all foaming stops.

The mixture is now of a dark brown color. Slip a piece
of wire gauze under tlie flask and slightly increase tlie heat

until the gauze is cherry red
where it comes in contact
with the Ijottom of the flask.
Place a funnel in the
neck of the flask to act as a
reflux condenser. Continue
heating until the contents
are colorless or of a pale
straw color. Tliis usually
takes from thirty minutes
to two hours. Conduct the
heating in a gas hood.

^Vlhjw the flask to cool.
Transfer tlie liquid hito a
Ijoiling flask of about oOOcc.
cap)acity, rinsing carefully
witli 200 cc. of water.

Add sufficient saturated
solution of NaOH to make
the contents strongly alkaline, using phenolphthalein as
an indicatoi'.

Place two or three pieces of zuic in the boiluig flask to
prevent bumping, and distil off at least 150 cc, using a ver-
tical conden.ser whose outlet dips below the surface of ex-
actly 50 cc. of N/10 H.,S(,)^ contained in the receiving flask.
(See apparatus for the detection of sulfurous acid.)

Fig. ii. Kjclduhl li;isk arraii-t'd lur
the detenniiialii.iii of iiitropjen

DETERMINATION OF FOOD VALUES

115

It is of the utmost importance to know the exact volume
of standard acid in the receiving flask. Measure with an
accurate pipette.

When all the ammonia has been distilled and absorbed,
titrate the contents of the receiving flask with N/10 NaOH,
using cochmeal as an indicator.

The difference between the original volume of the stand-
ard acid and the volume of N/10 NaOH required to titrate
it represents the number of cubic centimeters of N/10 H^SO^^

Fig. 25. Digesting shelf for making simultaneous nitrogen determinations

neutralized by the liberated ammonia. Every cubic centi-
meter of N/10 sulfuric acid represents .0014 g. of nitrogen.
The proteids are calculated from the total nitrogen by
multiplying by the factor 6.25. This factor is the one
generally adopted in determinations of this kind.

ExAMPLK. 'Weight of cereal = 0.5 g.
Volume of N/10 H^SO^ = 50 cc.
Required 44 cc. of N/10 NaOII to titrate the excess acid.
Therefore 6 cc. of N/10 H„S()j were neutralized by the liberated
ammonia.

1 cc. of N/IO HjSO^ = .0014 g. of nitrogen.
6 cc. of N/IO H2SO4 = 6 X .0014, or .0084 g. of nitrogen.
6.25 X .0084 = .0525 g. of proteid.

.0525/.5 = 10.5 per cent of proteid.

In such an analysis as the preceding one it is customary
to state that the Protein = 6.25 x N.

116

ELEilEXTAEY APPLIED CHEMISTEY

Fat of Cereal Products, known as "Ether Extract."
Weigh from 2 to 3 g. of the sample into a tared extraction
shell {^Schleirlwr and Sclinll). Dry thoroughly at 212°.

Place the shell m a Soxhlet or Wiley Extractor and
extract with water-free ether. Dry the shell and residue to

constant weight and by differ-
ence calculate the ether-solul)le
matter.

A thorough extraction re-
Cjuires several liours. (ireat
caution must lie exercised in
heating the extracting appara-
tus lest the ether take lire.
Use a large water liath and a
small flame, or, still better, an
electric stove.

Water or Moisture in Cereal
Products. Weigh from 2 to 5 g.
of the sample into a tared watch
glass. Spread it evenly over the
bottom, forming as thin a layer
as possible. Dry at 100°C.,cool.
and reweigh. Calculate the per
cent of water by ilifference.

Ash or Mineral Content of
Cereal Products. Transfer the
dried residue from the water determination to a tared porce-
lain crucible, taking care that none nf the sample is lost.
Burn to a white ash at the lowest temperature possiljle. If
too much heat is employed, i\w ash ^^ill fuse to the bitttom
(if the ci'uciblc. Cool in a desiccator, reweigh, and calculate
the per cent.

Fig. 26. Soxhlet extraction ap-
paratus properly set up

DETEEMINATION OF FOOD VALUES 117

Carbohydrates in Cereal Products. The carbohydrates are
often expressed by adding the per cent of water, ash, pro-
teids, and fat, and subtracting the sum from 100.

Calculation of Fuel Value. This value may be approxi-
mately determined by means of the Rubner factors, which
give for each pound of protein or carbohydrate 1860 calories,
and for each pound of fat 4220 calories.

Example. Suppose the analysis of a certain cereal product shows :
protein, 13.4 per cent ; carbohydrates, 74.1 per cent ; fat, 0.9 per cent.
Then 1860 x (.134 + .741) = 1627.50 calories

4220 X .009 = 37.98 calories
Total 1665.48

SECTION XXIII

TESTING UELN^Ei

Determine Reaction. Normal, sliglitly acid ; after a full
meal may be alkaline.

Determine Odor. Normal, peculiar, aromatic.

Determine Color. Normal, pale straw to reddish yellow.
May be very pale by nervousness or excessive drinking.

Determine Specific Gravity. Normal, 1.015 to 1.025 at
60° F.

Determine Total Solids. Normal, 3.4 per cent to 5.8 per
cent. Total solids equal (specific gravity — 1) multiplied
by 2.33. This is equivalent to the number of grams per
cubic centimeter.

To detect Albumen and Phosphates. First Method. Fill a
test tube half full of clear urine. Boil the upper portion
of the liquid. A turbidity indicates albumen or PO^, or
both. Add a drop of acetic or nitric acid ; the phosphates
dissolve, the albumen does not.

Second- 3Iethod. Place about a cubic centimeter of con-
centrated HNOg in a test tube, and by means of a pipette
allow two or three cubic centimeters of the urine to rest
upon its surface.

If albumen is present, a white zone or flocculent pre-
cipitate forms at the ring of contact of the two liquids.
The extent of turbidity indicates roughly the amount of
albumen present.

1 For more complete analysis see Merck's Manual for 1911.
118

TESTING URINE 119

A green turbidity indicates biliary pigments. Reddish
brown indicates blood.

Urates or Uric Acid. Murexide Test. Evaporate a few
drops of urine to dryness on a watch glass. Add a drop or
two of HNOj and again cautiously evaporate. Then add
an equal volume of NH^OH. A purple color indicates
urates, uric acid, or both.

Invert Sugar. Fehling's Test. Boil 5 cc. of Fehling's
solution, and if the color does not change, add an equal
volume (not more) of urine, and boil. In the presence of
reducing sugars the characteristic red-to-yellow precipitate
forms. (See tests for glucose.) Use this test only when
uric acid is absent.

Haines's Test. Reagents: CuSO^, 2g. ; glycerin, 20 g.;
KOH, 9g. ; water, 175 g. Boil 4 cc. of the solution and
add 6 to 10 drops (not more) of the urine and boil again.
In the presence of reducing sugars the yellow-to-red pre-
cipitate forms.

Detection of Sugar in the Presence of Urates or of Uric
Acid. Heat 1 g. of phenyldrazine hydrochlorate, 2 g. of
sodium acetate, and 25 cc. of urine, and if the salts do not
completely dissolve, add a little water, and place in boil-
ing water.

Remove after twenty minutes to cold water. If sugar is
present, characteristic crystals of phenylglucosazone form.

Chlorids. Add a few drops of nitric acid to the urine
to prevent the precipitation of the phosphates, and gradu-
ally add a few drops of AgNO^. A white precipitate solu-
ble in ammonia indicates chlorids. If present in small
quantity, a milky color only will be seen.

Sulfates. Use BaCl^ instead of the silver nitrate. If
present, the insoluble precipitate of BaSO^ will be seen.

SECTION XXIV

SELECTED EXERCISES

An Experiment with the Albumen of Meat. The most
important solid constituent of the body of an animal is
albumen. Place about 20 g. of lean beef finely minced in a
beaker of cold water and gradually heat to about 130° F.
Remove, filter the liquid, and test as follows :

To a portion add HNOj. A white precipitate or a decided
mUkiness indicates albumen.

To another portion add a few drops of iodin. A yellow
or port-wine color indicates the presence of glycogen or
animal starch.

Repeat the above experiment by placing the same weight
of beef in actively boiling water. Leave for a minute and
test as before. How do you account for the difference?
What does this show concerning the cooking of meats ?

Examination of Common Salt. Moisture. Purchase as
many different brands of table salt as possible ; also several
samples of " coarse-fine " and rock salt.

Place exactly 5 g. of the sample in a small tared Erlen-
meyer flask and heat to a temperature not exceeding 150° C.
for three hours on a sand bath. Remove from the bath, in-
sert a funnel in the mouth of the flask, and allow the contents
to cool. The introduction of the funnel renders the use of a
desiccator unnecessary for this determination. Reweigh, and
from the loss of weight calculate the per cent of moisture.
Reserve the residue for the determination of MgCl^.

120

SELECTED EXERCISES 121

Insoluble Matter. Dissolve 5 g. of the sample in 100 cc.
of water, heating gently if necessary. Filter the solution
through a balanced filter paper, washing the residue with
warm water until the filtrate shows no precipitate with
AgNOj solution. Dry' and weigh the contents of the filter
paper and calculate the per cent of insoluble matter.

Chlorin. Dissolve 5 g. of the undried sample in a little
water and make up the solution to exactly 500 cc. in a
measuring flask. Mix thoroughly and withdraw 10 cc. by
means of a pipette. Place in a clean beaker and add an equal
volume of distilled water. Titrate with N/10 AgNO^, using
neutral potassium chromate as an indicator (see p. 30). A
liter of N/10 silver nitrate contains 17 g. of the pure
crystallized salt.

Deduct 0.1 cc. of the silver solution added, as this amount
is required to produce the permanent red tinge. Every
cubic centimeter of the N/10 AgNO^ is equivalent to
0.00355 g. of chlorin.

The 10 cc. of the titrated salt solution contained, theo-
retically, how many grams of chlorin ? How many grams
did you find ? What was the per cent of chlorin ?

Suggestion. How many grams of salt did yoU dissolve ?
To what volume did you dilute it ? How many grams of
salt in 10 cc. of this solution ?

Calcium Sulfate. First Method. Dissolve 5 g. of the sample
in 20 cc. of water to which 2 cc. of HCl have been added.
Boil gently, being careful to lose none of the solution during
the process. In the case of rock salt it may be necessary to
continue the treatment for some time in order to dissolve
all of the CaSO.

Neutralize the solution with ammonia and precipitate
the calcium with (l:!m^')JOfi^. Allow it to stand overnight

122 ELEMENTARY APPLIED CHEMISTRY

and filter the solution through a fine, ashless filter paper.
Wash the residue carefully, dry, and ignite it in a weighed
crucible until the oxalate is converted into CaO. This will
require about twenty minutes at a white heat. Cool and
weigh as CaO. One part of CaO is equivalent to 2.4271
parts of CaSO^. Calculate the per cent of CaSO^ in the
original sample.

Second Method. Dissolve 10 g. of salt in warm water
containing 1 per cent of HCl. Dilute to a liter and draw
out 250 cc. (2.5 g. of salt). Heat this portion to boiling,
add 1 cc. of HCl, and immediately pour in about 20 cc. of
boiling 10 per cent BaCl^. Do not add the barium chlorid
solution drop by drop, but introduce it all at once. The
precipitate should settle in half an hour. Decant the clear
portion through an ashless filter paper. Pour 100 cc. of
boiling water on the precipitate, agitate, and allow to settle,
which it should do in about four minutes. Decant agam
and repeat the operation until the liquid ceases to give
an acid reaction. Finally wash the precipitate on the filter.
Dry, ignite at a low heat, and weigh the BaSO^. From this
calculate the per cent of CaSO^ in the sample.

, Magnesiilm Chlorid. Into the flask containing the dried
residue from the moisture determination place 25 cc. of abso-
lute alcohol. Cork the flask and gently shake the contents
from time to time for ten minutes. Filter and evaporate
the a,lcohol, which contains nothing but MgCl . Dissolve the
residue in water and titrate with N/10 AgNO^.

From the chlorin found calculate the per cent of MgCl^
in the sample.

WOKKING TABLE OF THE ELEMENTS 123

SYMBOLS, ATOMIC WEIGHTS, AND VALENCE OF THE
MORE IMPORTANT ELEMENTS

Element

Symbol

Atomic Weight

Valence

Aluminium

27.1

Antimony

120.2

3,5

Arsenic .

3,5

Barium

137.3

Bismuth

208

3, 5

Boron .

' 11

Bromin

79.9

Cadmium

112.4

Calcium

Carbon

Chlorin . .

35.5

Chromium .

52.1

2, 3, 6

Cobalt . . .

58.9

Copper

63.6

1,2

Fluorin . .

Gold . . ;

197.2

1,3

Hydrogen

lodin . . .

126.9

Iron . .

55.8

2,3

Lead . . .

207.1

2,4

Magnesium .

24.3

Manganese .

54.9

2,4

Mercury . .

200

1, 2

Nickel . . .

.58.6

Nitrogen . .

3,5

Oxygen .

Phosphorus .

3,5

Platinum . .

195

Potassium .

39.1

Silicon . .

28.3

Silver . . .

107.8

Sodium . .

Strontium

87.6

Sulfur . .

2,4,6

Tin. . . .

119

2,4

Zinc . . .

65.3

INDEX

Acetanilid, detection of, 102; de-
termination of, 104
Acetic acid, per cent of, 22
Acidity of milk, 20
Acids and alltalis, 5
Adulteration of milk, 45
Albumen, test for, 118
Alcohol, ethyl, 55; methyl, 60;

per cent of, 68 ; preparation of,

56 ; tables, 66
Alkali, free and combined in soap,

25
Alkaline carbonates in soap, 26
Alum, tests for, 39
Ammonia in baking powder, 39;

in water, detection of, 31
Ammonium molybdate solution,

33
Annatto, detection of, 45
Arsenic, tests for, 107
Artificial colors in milk, 45
Ash, of cereal products, 116; of

vinegar, 22
Atomic weights, table of, 123

Bach's table for oil. 111
Baking-powder analysis, 35
Baking soda, test for purity, 20;

in milk, 47
Barium sulfate in paint, 110
Bases in baking powder, 39
Borates in soap, 27
Boric acid, detection of, 91
Boron in milk, 47

Butter, boron compounds in, 92;
coal-tar dye in, 77 ; renovated, to
distinguish, 112

Calcium carbonate in soils, 9
Calcium sucrate in cream, 48
Calcium sulfate in salt, 121
Cane sugar, inversion of, 98
Caramel, detection of, 79
Carbohydrates in cereal products,

117
Carbon dioxid in baking powders, 35
Cheese, fat in, 52
Chlorids in plants, 15
Chlorin, in salt, 121 ; in water,

tests for, 30
Chlorophyl, extraction of, 13
Cider vinegar, to distinguish, 23
Citric acjd, per cent of, 19
Cloth, arsenic in, 106
Coal-tar dye, detection of, 76
Cochineal, 80
Cocoa, purity of, 24
Condensed milk, fat in, 53 ; times

condensed, 53
Cottonseed oil in olive oil. 111
Cream, determination of fat in, 52

Dirt in milk, 44
Distillation experiments, 54

Equivalents of N/10 NaOH, 19
Erythrosin as an indicator, 34
Essential oils, extraction of, 44

125

126

ELEMENTAEY APPLIED CHEMISTRY

Fabrics, wool and cotton in, 7
Fat, in cereal products, 116 ; in

milk by the Babcock test, 41
Fatty acids in olive oil, 110
Fehling's solution, 98
Filtration experiments, 1
Flame tests, 10
Food preservatives, 90
Food values, determination of, 113
Formaldehyde in milk, 46
Fuel values, calories, 117

Gelatin in milk, cream, etc., 48
Glucose, preparation of, 97 ; tests

for, 98
Gunning's method for nitrogen,

115
Gunpowder, analysis of, 2

Hardness of water, 34
Headache powders, analysis of, 102
Honey, glucose in, 99
Hydrochloric acid in soils, 10

Ice cream, fat in, 52 ; gelatin in,
48 ; starch in, 52

Ink eradicator, 88

Invert sugar, in honey, 99 ; in veg-
etables, 100

Iron in plants, 15

Iron oxid in soils, 9

Lactic acid, per cent of, 20

Lead in paint, 110

Lemon extract, coal-tar dye in, 78 ;
per cent of oil in, 65; prepara-
tion of, 64

Lime in paint, 110

Litmus, use of, 5

Magnesium in soils, ll ; chlorid in
salt, 122

Maple sirup, tests for purity, 100

Martin's reagent, 78

Metallic compounds in water, 34

Methyl orange as an indicator, 34

Milk analysis, 41

Mineral acids in vinegar, 23

Nessler's reagent, 31
Nitrate of mercury, acid, 49
Nitrates and nitrites, detection of,

in water, 32
Nitric acid in soils, 11
Nitrogen, determination of, 115 ;

in plants, 13

Oil, extraction of, from paint, 109 ;

olive, examination of, 110
Oleomargarine, to detect, 112
Oxalic acid N/10, 17
Oxygen absorbed in water, 33
Oystere, water in, 4

Paint analysis, 109
Phenolphthalein as an indicator, 17
Phosphates in water, 32
Phosphoric acid, in plants, 15; in

soils, 11
Plant analysis, 13
Potash, in plants, 14 ; In soils, 10
Potassium sulfo-cyanide test, 10
Preservatives in milk, 46
Proteins, determination of, 115
Pumice stone in tooth powder, 95

Radicals in baking powder, 38
Raffia dyeing, 81

Richmond scale for total solids in
milk, 44

Saccharin, detection of, 94
Salicylic acid, detection of, 93
Salt analysis, 120

INDEX

12T

Sand in soils, 11

Sediment in water, 28

Silica in plants, 15

Skimmed milk, identification of, 51

Soap, analysis of, 25; insoluble mat-
ter in, 25

Soda, in plants, 14 ; in soils, 10

Sodium bicarbonate in milk, 47

Sodium hydrate N/10, 17

Soil analysis, 9

Soils, acidity and alkalinity of, 24

Specific gravity of milk, 43

Stains, chemistry of, 88

Standard solutions, 16 ; exercises
with, 19

Starch, conversion to invert sugar,
97 ; effect of mastication on,
100 ; test for, 14

Sugar in urine, detection of, 119

Sulfates, in plants, 15 ; in soils, 10

Sulfuric acid, in soils, 10; in vine-
gar, 23

Sulfurous acid, detection of, 90;
determination of, 91

Tartrates, test for, 88
Tea, soluble matter in, 3

Theine, extraction of, 4

Titration, 16

Tonsillitis Specific, 1

Tooth powder, examination of, 95

Total solids, in milk, 43 ; in water,

29
Turmeric, tests for, 80
Turmeric tincture, preparation of,

Urine analysis, 118

Vanilla extract, preparation of, 62 ;

tests for, 63
Vegetable colors, identification of,

79
Vinegar analysis, 21
Vinegar eels, 21

Wall paper, arsenic in, 106

Water, analysis of, 28 ; in cereal
products, 116; in milk, detec-
tion of, 51

Waterhouse test for butter, 112

Wool in fabrics, 7

Zinc in paint, detection of, 110

ANNOUNCEMENTS

AN ELEMENTARY STUDY OF
CHEMISTRY

By WILLIAM McPHERSON, Professor of Chemistry in Ohio State University,
and WILLIAM E. HENDERSON, Associate Professor of Chemistry in
Ohio State University.

I2mo, cloth, 434 pages, illustrated, ^1.25

THIS book is the outgrowth of many years of experience in
the teaching of elementary chemistry. In its preparation
the authors have steadfastly kept in mind the limitations
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endeavored to present the subject in a clear, well-graded way,
passing in a natural and logical manner from principles which are
readily understood to those which are more difficult to grasp.
The language is simple and as free as possible from unusual and
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The book is in no way radical, either in the subject-matter
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and well within the reach of the ability of an elementary student.
The most recent discoveries have been touched upon where they
come within the scope of an elementary text. Especial attention
has been given to the practical applications of chemistry, and to
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EXERCISES IN CHEMISTRY. By William McPhersoN and
William E. Henderson. 40 cents. In Biflex Binder, 60 cents.

GINN & COMPANY Publishers

PURE FOODS

THEIR ADULTERATION, NUTRITIVE VALUE,
AND COST

By John C. Olsen, Professor of Analytical Chemistry, Polytechnic Institute of
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i2mo, cloth, 2IO pages, illustrated, 80 cents

"" Pure Foods : their Adulteration, Nutritive Value, and Cost"
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There is a statement of legal requirements for pure foods,
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This volume is admirably adapted for use in domestic science
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165H

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